fix a bug in doing interpolation for upper/lower limits when there the points are not crossing the line
fix a bug in doing interpolation for upper/lower limits when there the points are not crossing the line


git-svn-id: ecbadac9c76e8cf640a0bca86f6bd796c98521e3@44145 27541ba8-7e3a-0410-8455-c3a389f83636

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