vacation.pl: applying patch from luxten - see https://sourceforge.net/tracker/index.php?func=detail&aid=2031659&group_id=191583&atid=937966 - thanks!

git-svn-id: https://svn.code.sf.net/p/postfixadmin/code/trunk@427 a1433add-5e2c-0410-b055-b7f2511e0802

VIRTUAL_VACATION/vacation.pl

@@ -164,7 +164,7 @@ sub already_notified {
 
 # Violation of a primay key constraint may happen here, and that's
 # fine. All other error conditions are not fine, however.
-      if ($e !~ /_pkey/) {
+      if ($e !~ /(?:_pkey|^Duplicate entry)/) {
          do_log('',$to,$from,'',"Unexpected error: '$e' from query '$query'");
 
          # Let's play safe and notify anyway