added missing Makefile.am

git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@7309 2fb0f335-1f38-0410-981e-8018bf24f1b0

dumux/Makefile.am

-SUBDIRS = boxmodels common decoupled io material nonlinear
+SUBDIRS = boxmodels common decoupled io linear material nonlinear parallel
 
 dumuxdir = $(includedir)/dune/dumux
 

dumux/parallel/Makefile.am

+paralleldir = $(includedir)/dune/dumux/parallel
+parallel_HEADERS = *.hh
+
+include $(top_srcdir)/am/global-rules