Makes sure that the status object is always defined

In the MPIC_Sendrecv functions, the status object should always be defined
since we use it internally. This won't have any impact on performance since
the default is always to have FT collectives turned on anyway, but it will
prevent a crash when someone overwrites that default.

Fixes #2026
Signed-off-by: Sangmin Seo <sseo@anl.gov>

src/mpi/coll/helper_fns.c

@@ -458,10 +458,9 @@ int MPIC_Sendrecv(const void *sendbuf, int sendcount, MPI_Datatype sendtype,
     context_id = (comm_ptr->comm_kind == MPID_INTRACOMM) ?
         MPID_CONTEXT_INTRA_COLL : MPID_CONTEXT_INTER_COLL;
 
-    if (MPIR_CVAR_ENABLE_COLL_FT_RET) {
-        if (status == MPI_STATUS_IGNORE) status = &mystatus;
+    if (status == MPI_STATUS_IGNORE) status = &mystatus;
+    if (MPIR_CVAR_ENABLE_COLL_FT_RET)
         if (*errflag) MPIR_TAG_SET_ERROR_BIT(sendtag);
-    }
 
     mpi_errno = MPID_Irecv(recvbuf, recvcount, recvtype, source, recvtag,
                            comm_ptr, context_id, &recv_req_ptr);
@@ -536,10 +535,9 @@ int MPIC_Sendrecv_replace(void *buf, int count, MPI_Datatype datatype,
     MPIU_ERR_CHKANDJUMP1((count < 0), mpi_errno, MPI_ERR_COUNT,
                          "**countneg", "**countneg %d", count);
 
-    if (MPIR_CVAR_ENABLE_COLL_FT_RET) {
-        if (status == MPI_STATUS_IGNORE) status = &mystatus;
+    if (status == MPI_STATUS_IGNORE) status = &mystatus;
+    if (MPIR_CVAR_ENABLE_COLL_FT_RET)
         if (*errflag) MPIR_TAG_SET_ERROR_BIT(sendtag);
-    }
 
     MPID_Comm_get_ptr(comm, comm_ptr);
     context_id_offset = (comm_ptr->comm_kind == MPID_INTRACOMM) ?