CustomVariable: Fix some mistakes

library/Director/CustomVariable/CustomVariableArray.php

@@ -12,4 +12,10 @@ class CustomVariableArray extends CustomVariable
 
         return $var->getValue() === $this->getValue();
     }
+
+    public function toConfigString()
+    {
+        // TODO: Implement toConfigString() method.
+    }
+
 }

library/Director/CustomVariable/CustomVariableDictionary.php

@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Director\CustomVariable;
 
+use Countable;
+
 class CustomVariableDictionary extends CustomVariable implements Countable
 {
     public function equals(CustomVariable $var)
@@ -48,4 +50,9 @@ class CustomVariableDictionary extends CustomVariable implements Countable
     {
         // ...
     }
+
+    public function toConfigString()
+    {
+        // TODO: Implement toConfigString() method.
+    }
 }

library/Director/CustomVariable/CustomVariableString.php

@@ -15,7 +15,7 @@ class CustomVariableString extends CustomVariable
     {
         return c::renderKeyValue(
             c::escapeIfReserved($this->getKey()),
-            c::renderString($this->getValue()
+            c::renderString($this->getValue())
         );
     }
 }

library/Director/CustomVariable/CustomVariables.php

@@ -38,7 +38,7 @@ class CustomVariables
 
     public function hasBeenModified()
     {
-        return $this->modifiec
+        return $this->modifiec;
     }
 
     public function setUnmodified()