IDO PgSQL: always use regular string literals

IdoPgsqlConnection::Escape() internally uses PQescapeStringConn() and its
documentation states the following:

  Furthermore, PQescapeStringConn does not generate the single quotes that must
  surround PostgreSQL string literals; they should be provided in the SQL
  command that the result is inserted into.

So it's intended to use the result in 'string' literals, not in E'string'
literals as Icinga did. This results in problems as the behavior of
PQescapeStringConn() depends on how the current connection will interpret
regular single quoted literals, namely on the value of the
standard_conforming_strings variable.

The E'string' literals were initially introduced in
ac6f3f8acf to fix #1206 where PostgreSQL started
warning about escape sequences in string literals not supported by the SQL
standard (but by PostgreSQL depending on the value of
standard_conforming_strings). In the meantime the oldest PostgreSQL version on
any platform supported by Icinga increased to 9.2 (CentOS 7) and starting with
9.1, standard_conforming_strings is enabled by default, so there will be no
warnings about escape sequences (as the warning is only issued if the escape
sequence is actually interpreted by PostgreSQL).

lib/db_ido_pgsql/idopgsqlconnection.cpp

@@ -263,7 +263,7 @@ void IdoPgsqlConnection::Reconnect()
 
 	String dbVersionName = "idoutils";
 	IncreasePendingQueries(1);
-	result = Query("SELECT version FROM " + GetTablePrefix() + "dbversion WHERE name=E'" + Escape(dbVersionName) + "'");
+	result = Query("SELECT version FROM " + GetTablePrefix() + "dbversion WHERE name='" + Escape(dbVersionName) + "'");
 
 	Dictionary::Ptr row = FetchRow(result, 0);
 
@@ -295,12 +295,12 @@ void IdoPgsqlConnection::Reconnect()
 	String instanceName = GetInstanceName();
 
 	IncreasePendingQueries(1);
-	result = Query("SELECT instance_id FROM " + GetTablePrefix() + "instances WHERE instance_name = E'" + Escape(instanceName) + "'");
+	result = Query("SELECT instance_id FROM " + GetTablePrefix() + "instances WHERE instance_name = '" + Escape(instanceName) + "'");
 	row = FetchRow(result, 0);
 
 	if (!row) {
 		IncreasePendingQueries(1);
-		Query("INSERT INTO " + GetTablePrefix() + "instances (instance_name, instance_description) VALUES (E'" + Escape(instanceName) + "', E'" + Escape(GetInstanceDescription()) + "')");
+		Query("INSERT INTO " + GetTablePrefix() + "instances (instance_name, instance_description) VALUES ('" + Escape(instanceName) + "', '" + Escape(GetInstanceDescription()) + "')");
 		m_InstanceID = GetSequenceValue(GetTablePrefix() + "instances", "instance_id");
 	} else {
 		m_InstanceID = DbReference(row->Get("instance_id"));
@@ -384,8 +384,8 @@ void IdoPgsqlConnection::Reconnect()
 	IncreasePendingQueries(1);
 	Query("INSERT INTO " + GetTablePrefix() + "conninfo " +
 		"(instance_id, connect_time, last_checkin_time, agent_name, agent_version, connect_type, data_start_time) VALUES ("
-		+ Convert::ToString(static_cast<long>(m_InstanceID)) + ", NOW(), NOW(), E'icinga2 db_ido_pgsql', E'" + Escape(Application::GetAppVersion())
+		+ Convert::ToString(static_cast<long>(m_InstanceID)) + ", NOW(), NOW(), 'icinga2 db_ido_pgsql', '" + Escape(Application::GetAppVersion())
-		+ "', E'" + (reconnect ? "RECONNECT" : "INITIAL") + "', NOW())");
+		+ "', '" + (reconnect ? "RECONNECT" : "INITIAL") + "', NOW())");
 
 	/* clear config tables for the initial config dump */
 	PrepareDatabase();
@@ -522,7 +522,7 @@ DbReference IdoPgsqlConnection::GetSequenceValue(const String& table, const Stri
 	AssertOnWorkQueue();
 
 	IncreasePendingQueries(1);
-	IdoPgsqlResult result = Query("SELECT CURRVAL(pg_get_serial_sequence(E'" + Escape(table) + "', E'" + Escape(column) + "')) AS id");
+	IdoPgsqlResult result = Query("SELECT CURRVAL(pg_get_serial_sequence('" + Escape(table) + "', '" + Escape(column) + "')) AS id");
 
 	Dictionary::Ptr row = FetchRow(result, 0);
 
@@ -604,11 +604,11 @@ void IdoPgsqlConnection::InternalActivateObject(const DbObject::Ptr& dbobj)
 		if (!dbobj->GetName2().IsEmpty()) {
 			qbuf << "INSERT INTO " + GetTablePrefix() + "objects (instance_id, objecttype_id, name1, name2, is_active) VALUES ("
 				<< static_cast<long>(m_InstanceID) << ", " << dbobj->GetType()->GetTypeID() << ", "
-				<< "E'" << Escape(dbobj->GetName1()) << "', E'" << Escape(dbobj->GetName2()) << "', 1)";
+				<< "'" << Escape(dbobj->GetName1()) << "', '" << Escape(dbobj->GetName2()) << "', 1)";
 		} else {
 			qbuf << "INSERT INTO " + GetTablePrefix() + "objects (instance_id, objecttype_id, name1, is_active) VALUES ("
 				<< static_cast<long>(m_InstanceID) << ", " << dbobj->GetType()->GetTypeID() << ", "
-				<< "E'" << Escape(dbobj->GetName1()) << "', 1)";
+				<< "'" << Escape(dbobj->GetName1()) << "', 1)";
 		}
 
 		IncreasePendingQueries(1);
@@ -719,7 +719,7 @@ bool IdoPgsqlConnection::FieldToEscapedString(const String& key, const Value& va
 		else
 			fvalue = rawvalue;
 
-		*result = "E'" + Escape(fvalue) + "'";
+		*result = "'" + Escape(fvalue) + "'";
 	}
 
 	return true;