Fix  the hiden operator=


git-svn-id: svn+ssh://svn.cern.ch/reps/atlasoff/Control/AthenaKernel/branches/AthenaKernel-00-53-04-branch@566057 4525493e-7705-40b1-a816-d608a930855b
Fix the operator=


git-svn-id: svn+ssh://svn.cern.ch/reps/atlasoff/Control/AthenaKernel/branches/AthenaKernel-00-53-04-branch@566060 4525493e-7705-40b1-a816-d608a930855b
Restore operator = return type


git-svn-id: svn+ssh://svn.cern.ch/reps/atlasoff/Control/AthenaKernel/branches/AthenaKernel-00-53-04-branch@566109 4525493e-7705-40b1-a816-d608a930855b