Remove some unused variables / silence some compiler warnings

This commit was SVN r22419.

ompi/communicator/comm_cid.c

@@ -157,8 +157,7 @@ int ompi_comm_nextcid ( ompi_communicator_t* newcomm,
                         void* remote_leader,
                         int mode, int send_first )
 {
-    int nextcid, block;
+    int nextcid;
-    int global_block_start;
     bool flag;
     int nextlocal_cid;
     int done=0;