- In GetHistogram: fix the problem mentionned here:   http://root.cern.ch/phpBB2/viewtopic.php?p=35256#35256   fHistogram is returned immediatly if it exists unless the log scale    is ON and the computed minimum is greater than zero. In that case the    histogram needs to be recomputed.
- In GetHistogram: fix the problem mentionned here:
  http://root.cern.ch/phpBB2/viewtopic.php?p=35256#35256
  fHistogram is returned immediatly if it exists unless the log scale 
  is ON and the computed minimum is greater than zero. In that case the 
  histogram needs to be recomputed.


git-svn-id: ecbadac9c76e8cf640a0bca86f6bd796c98521e3@28200 27541ba8-7e3a-0410-8455-c3a389f83636

dawehner/root,dawehner/root,bbannier/ROOT,bbannier/ROOT,dawehner/root,dawehner/root,dawehner/root,dawehner/root,bbannier/ROOT,bbannier/ROOT,bbannier/ROOT,bbannier/ROOT,bbannier/ROOT,dawehner/root,dawehner/root