Fix bash line continuation in mail-host-notification.sh

etc/icinga2/scripts/mail-host-notification.sh

@@ -178,7 +178,7 @@ if [ -n "$MAILFROM" ] ; then
 
   ## Debian/Ubuntu use mailutils which requires `-a` to append the header
   if [ -f /etc/debian_version ]; then
-    /usr/bin/printf "%b" "$NOTIFICATION_MESSAGE"  | tr -d '\015'
+    /usr/bin/printf "%b" "$NOTIFICATION_MESSAGE"  | tr -d '\015' \
     | $MAILBIN -a "From: $MAILFROM" -s "$ENCODED_SUBJECT" $USEREMAIL
   ## Other distributions (RHEL/SUSE/etc.) prefer mailx which sets a sender address with `-r`
   else