mfem deps issue

[cyrush]

when cuda is on, mfem will add xlinker flags for rpaths in this config.mk.

This is not needed (we are using static libs) and also breaks linking, when not linking with nvcc.

_BLT_MFEM_LIBRARIES:STRING=/ccs/home/cyrush/WORKSCRATCH/2021_11_ascent_spock/devil_ray/ul_summit/spack/opt/spack/linux-rhel8-power9le/gcc-9.3.0/mfem-4.3.0-5t33q7lctkn3f5buzooxprgj64jl6ezq/lib/libmfem.a;-Xlinker=-rpath,/gpfs/alpine/csc340/proj-shared/cyrush/2021_11_ascent_spock/devil_ray/ul_summit/spack/opt/spack/linux-rhel8-power9le/gcc-9.3.0/metis-5.1.0-rkeroeskvlmbl5n5byxlq7enfieb6dm5/lib -L/gpfs/alpine/csc340/proj-shared/cyrush/2021_11_ascent_spock/devil_ray/ul_summit/spack/opt/spack/linux-rhel8-power9le/gcc-9.3.0/metis-5.1.0-rkeroeskvlmbl5n5byxlq7enfieb6dm5/lib -lmetis -Xlinker=-rpath,/gpfs/alpine/csc340/proj-shared/cyrush/2021_11_ascent_spock/devil_ray/ul_summit/spack/opt/spack/linux-rhel8-power9le/gcc-9.3.0/conduit-develop-qjkcruxac6vgcccvdt7b4fbhwikyydi5/lib -Xlinker=-rpath,/gpfs/alpine/csc340/proj-shared/cyrush/2021_11_ascent_spock/devil_ray/ul_summit/spack/opt/spack/linux-rhel8-power9le/gcc-9.3.0/hdf5-1.8.22-kgdmsqegjqvxxh657pledpwd4ujjrhdv/lib -L/gpfs/alpine/csc340/proj-shared/cyrush/2021_11_ascent_spock/devil_ray/ul_summit/spack/opt/spack/linux-rhel8-power9le/gcc-9.3.0/conduit-develop-qjkcruxac6vgcccvdt7b4fbhwikyydi5/lib -L/gpfs/alpine/csc340/proj-shared/cyrush/2021_11_ascent_spock/devil_ray/ul_summit/spack/opt/spack/linux-rhel8-power9le/gcc-9.3.0/hdf5-1.8.22-kgdmsqegjqvxxh657pledpwd4ujjrhdv/lib -lconduit -lconduit_relay -lconduit_blueprint -ldl -lhdf5 -lcusparse -lrt -Xlinker=-rpath,/gpfs/alpine/csc340/proj-shared/cyrush/2021_11_ascent_spock/devil_ray/ul_summit/spack/opt/spack/linux-rhel8-power9le/gcc-9.3.0/zlib-1.2.11-rdawe4aulcnwgz2teu5m25p3fgsfxocr/lib -L/gpfs/alpine/csc340/proj-shared/cyrush/2021_11_ascent_spock/devil_ray/ul_summit/spack/opt/spack/linux-rhel8-power9le/gcc-9.3.0/zlib-1.2.11-rdawe4aulcnwgz2teu5m25p3fgsfxocr/lib -lz