Revert the behavior of SHOW command without a database connection. It makes sense for SHOW SQL DIALECT.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59287 65644016-39b1-43b1-bf79-96bc8fe82c15
Warnings.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59288 65644016-39b1-43b1-bf79-96bc8fe82c15