generalized data_type, request, and status to be structs for the case when MPI is absent.  These are only needed to complete function signatures.
generalized data_type, request, and status to be structs for the case when MPI is absent.  These are only needed to complete function signatures.

git-svn-id: ffc1bc5b3feaf8644044862cc38c386ade156493@3141 434f946d-2f3d-0410-ba4c-cb9f52fb0dbf

certik/libmesh,certik/libmesh,certik/libmesh,certik/libmesh,certik/libmesh,certik/libmesh,certik/libmesh