Import patch 48355:
From Dario, in TDataSetManagerAliEn:
 - fixed-length cache file names to avoid length problems;
 - fixed debug messages;
 - added very important Anchor= option in AliEn find mode.


git-svn-id: https://root.cern.ch/svn/root/branches/v5-34-00-patches@48356 27541ba8-7e3a-0410-8455-c3a389f83636