fix FillRandom(hist) for case of histograms with different axis,  see https://sft.its.cern.ch/jira/browse/ROOT-4938
fix FillRandom(hist) for case of histograms with different axis, 
see https://sft.its.cern.ch/jira/browse/ROOT-4938


git-svn-id: ecbadac9c76e8cf640a0bca86f6bd796c98521e3@49214 27541ba8-7e3a-0410-8455-c3a389f83636

bbannier/ROOT,bbannier/ROOT,bbannier/ROOT,bbannier/ROOT,bbannier/ROOT,bbannier/ROOT,bbannier/ROOT