mtl/ofi: fix problem with mprobe/mrecv

At least with some providers (sockets and GNI), the mprobe/mrecv
ofi mtl methods were incorrect.  For these two providers at least
one must supply the original tag and mask bits used with the
prior FI_PEEK | FI_CLAIM request that had been used to probe for
the message.

These providers take a strict interpretation of the following sentence
from the libfabric fi_tagged man page:

```
 Claimed messages can only be retrieved using a subsequent, paired receive  operation  with  the  FI_CLAIM  flag  set.
```

Signed-off-by: Howard Pritchard <howardp@lanl.gov>

ompi/mca/mtl/ofi/mtl_ofi.h

@@ -1,5 +1,7 @@
 /*
  * Copyright (c) 2013-2017 Intel, Inc. All rights reserved
+ * Copyright (c) 2017      Los Alamos National Security, LLC. All rights
+ *                         reserved.
  *
  * $COPYRIGHT$
  *
@@ -686,8 +688,8 @@ ompi_mtl_ofi_imrecv(struct mca_mtl_base_module_t *mtl,
     msg.desc = NULL;
     msg.iov_count = 1;
     msg.addr = 0;
-    msg.tag = 0;
-    msg.ignore = 0;
+    msg.tag = ofi_req->match_bits;
+    msg.ignore = ofi_req->mask_bits;
     msg.context = (void *)&ofi_req->ctx;
     msg.data = 0;
 
@@ -868,6 +870,7 @@ ompi_mtl_ofi_improbe(struct mca_mtl_base_module_t *mtl,
     ofi_req->error_callback = ompi_mtl_ofi_probe_error_callback;
     ofi_req->completion_count = 1;
     ofi_req->match_state = 0;
+    ofi_req->mask_bits = mask_bits;
 
     MTL_OFI_RETRY_UNTIL_DONE(fi_trecvmsg(ompi_mtl_ofi.ep, &msg, msgflags));
     if (-FI_ENOMSG == ret) {

ompi/mca/mtl/ofi/mtl_ofi_request.h

@@ -1,5 +1,7 @@
 /*
  * Copyright (c) 2013-2016 Intel, Inc. All rights reserved
+ * Copyright (c) 2017      Los Alamos National Security, LLC. All rights
+ *                         reserved.
  *
  * $COPYRIGHT$
  *
@@ -71,9 +73,12 @@ struct ompi_mtl_ofi_request_t {
     /** Flag to prevent MPI_Cancel from cancelling a started Recv request */
     volatile bool req_started;
 
-    /** Request's tag used in case of an error. */
+    /** Request's tag used in case of an error. Also for FI_CLAIM requests. */
     uint64_t match_bits;
 
+    /** Used to build msg for fi_trecvmsg with FI_CLAIM  */
+    uint64_t mask_bits;
+
     /** Remote OFI address used when a Recv needs to be ACKed */
     fi_addr_t remote_addr;