revert changes in nonequilibriumfluidstate.hh made in revision 7333

AFAICS it was only debugging code which was not useful in a general
context...

git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@7335 2fb0f335-1f38-0410-981e-8018bf24f1b0