Fixed crash due restore from backup after DDL permissions implementation and changed prefix of SC to general SQL$ to skip backuping such classes by standard way.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59878 65644016-39b1-43b1-bf79-96bc8fe82c15
More fixes for the explained plan output.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59879 65644016-39b1-43b1-bf79-96bc8fe82c15