Fixed minor bugs
CORE-4250 : AV in guardian at process shutdown
CORE-4251 : Guardian service could write garbage after the end of message in the Event Log
and clean up a bit

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/branches/B2_5_Release@58712 65644016-39b1-43b1-bf79-96bc8fe82c15