Requested changes related to mumps compilation (#4614)

*  * add mpii* wrappers for use with intel compilers

 * in mumps package, scotch is compiled without metis option when
   ptscotch variant is selected. This removes confusion over which
   metis.h to use

 * for intel mkl, add SPACK_COMPILER_EXTRA_RPATHS ending in 'intel64'

 * scotch lib requires libz when compression is turned on.  This
   caused a link issue on some Ubuntu distributions (not
   redhat). Change Scotch package to add -lz when needed

*  * intel-mkl append to SPACK_COMPILER_EXTRA_RPATHS rather than setting

 * use more concise method to obtain libz libraries for scotch

* remove changes to intel mpi

* remove commented out depends_on

* fix flake8 errors

var/spack/repos/builtin/packages/intel-mkl/package.py

@@ -142,6 +142,8 @@ def install(self, spec, prefix):
     def setup_dependent_environment(self, spack_env, run_env, dependent_spec):
         # set up MKLROOT for everyone using MKL package
         spack_env.set('MKLROOT', self.prefix)
+        spack_env.append_path('SPACK_COMPILER_EXTRA_RPATHS',
+                              join_path(self.prefix.lib, 'intel64'))
 
     def setup_environment(self, spack_env, run_env):
         run_env.set('MKLROOT', self.prefix)