Fix memchecker usage in these functions -- these variables are not

used.  They're just copy-n-paste errors from the MPI_Reduce_scatter
variants. 

This commit was SVN r26669.

ompi/mpi/c/ireduce_scatter_block.c

@@ -48,9 +48,6 @@ int MPI_Ireduce_scatter_block(void *sendbuf, void *recvbuf, int recvcount,
     MEMCHECKER(
         int rank;
 
-        size = ompi_comm_size(comm);
-        rank = ompi_comm_rank(comm);
-
         memchecker_comm(comm);
         memchecker_datatype(datatype);
         

ompi/mpi/c/reduce_scatter_block.c

@@ -47,9 +47,6 @@ int MPI_Reduce_scatter_block(void *sendbuf, void *recvbuf, int recvcount,
     MEMCHECKER(
         int rank;
         
-        size = ompi_comm_size(comm);
-        rank = ompi_comm_rank(comm);
-
         memchecker_comm(comm);
         memchecker_datatype(datatype);