fhem.pl: check for undefined motd


git-svn-id: svn://svn.code.sf.net/p/fhem/code/trunk@5503 2b470e98-0d58-463d-a4d8-8e2adae1ed80
bugfixing

git-svn-id: svn://svn.code.sf.net/p/fhem/code/trunk@5504 2b470e98-0d58-463d-a4d8-8e2adae1ed80