add metadata write on stop


git-svn-id: svn+ssh://svn.cern.ch/reps/atlasoff/Database/AthenaRoot/AthenaRootComps/trunk@566842 4525493e-7705-40b1-a816-d608a930855b
add a warning about the metadata


git-svn-id: svn+ssh://svn.cern.ch/reps/atlasoff/Database/AthenaRoot/AthenaRootComps/trunk@566850 4525493e-7705-40b1-a816-d608a930855b