Patch for initializing TGeoBranchArray objects from the navigator pointing to the top volume


git-svn-id: https://root.cern.ch/svn/root/branches/v5-34-00-patches@49268 27541ba8-7e3a-0410-8455-c3a389f83636
Finalize r49010; fixes ROOT-5054.


git-svn-id: https://root.cern.ch/svn/root/branches/v5-34-00-patches@49269 27541ba8-7e3a-0410-8455-c3a389f83636