[CMake] Remove deprecated code parts for DUMUX_ALWAYS_INLINE.

This caused a invalid config.h.
Improve an other CMake test: C files should always have an empty line at
the end.


git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@11848 2fb0f335-1f38-0410-981e-8018bf24f1b0