- vacation.pl: replace DBD::MySQL with DBD::mysql in a comment.

Reported in the forum by jlbrown1:
  https://sourceforge.net/forum/message.php?msg_id=4563099


git-svn-id: https://svn.code.sf.net/p/postfixadmin/code/trunk@150 a1433add-5e2c-0410-b055-b7f2511e0802

VIRTUAL_VACATION/vacation.pl

@@ -38,7 +38,7 @@
 #
 #
 # Requirements:
-# You need to have the DBD::Pg or DBD::MySQL perl-module installed.
+# You need to have the DBD::Pg or DBD::mysql perl-module installed.
 # You need to have the Mail::Sendmail module installed. 
 # You need to have the Email::Valid module installed.
 # You need to have the MIME::Charset module installed.