metis search is triggered in DUNE_PATH_PARMETIS now! Skip it here.

[[Imported from SVN: r1657]]

m4/dune_istl.m4

 AC_DEFUN([DUNE_ISTL_CHECKS],
 [
-  # call IMDX_LIB_METIS directly and not via AC_REQUIRE
-  # because AC_REQUIRE support not allow parameters
-  IMMDX_LIB_METIS(,[true])
   AC_REQUIRE([DUNE_PATH_PARMETIS])
   AC_REQUIRE([DUNE_PATH_SUPERLU])
   AC_REQUIRE([DUNE_PATH_SUPERLU_DIST])