Fixed CORE-4132: gbak requires exclusive access.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@58279 65644016-39b1-43b1-bf79-96bc8fe82c15
Misc.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@58281 65644016-39b1-43b1-bf79-96bc8fe82c15