Renamed "Add Child" to "Create Child" and fixed a query errors in bug_copy() + replace if ( xxx = true ) with if ( xxx )

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@2717 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9