use noRounding for the Poisson of the sidebands since the noff value can be in...

use noRounding for the Poisson of the sidebands since the noff value can be in some cause non-integer (i.e. be interpreted as a Gamma constraint)


git-svn-id: http://root.cern.ch/svn/root/trunk@43932 27541ba8-7e3a-0410-8455-c3a389f83636