[BugFix] Disable MPI if --enable-parallel is not found. Previously,

this was the other way around.

[[Imported from SVN: r7458]]

lib/dunecommonam2cmake.lib

@@ -21,7 +21,7 @@ dune_common_options_am2cmake()
 
     # Check for --enable-parallel and otherwise deactivate MPI
     echo $PARAMS | grep \\-\\-enable-parallel
-    if test "$?" -eq 0 ; then
+    if test "$?" -ne 0 ; then
 	CMAKE_PARAMS="$CMAKE_PARAMS -DCMAKE_DISABLE_FIND_PACKAGE_MPI=TRUE"
     fi
     # Check for --disable-gxx0xcheck