splinecommon: remove superfluous and erroneous special treatment of the "get"...

splinecommon: remove superfluous and erroneous special treatment of the "get" functionality for older compilers. Meanwhile, Dune takes care of that.

git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@8818 2fb0f335-1f38-0410-981e-8018bf24f1b0