optimize Parallel::send_receive() for the case when the source and destination are both the local processor.
optimize Parallel::send_receive() for the case when the source and destination are both the local processor.

git-svn-id: ffc1bc5b3feaf8644044862cc38c386ade156493@2712 434f946d-2f3d-0410-ba4c-cb9f52fb0dbf

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