configury + btl/openib: fix a typo

test for existence of struct ibv_exp_device_attr.exp_atomic_cap.
That was previously mistyped struct ibv_exp_device_attr.ext_atomic_cap

(back-ported from commit open-mpi/ompi@1b3be0a)

Author: ggouaillardet

config/opal_check_openfabrics.m4

@@ -17,7 +17,7 @@
 # Copyright (c) 2010-2012 Oracle and/or its affiliates.  All rights reserved.
 # Copyright (c) 2009-2012 Oak Ridge National Laboratory.  All rights reserved.
 # Copyright (c) 2014      Bull SAS.  All rights reserved.
-# Copyright (c) 2014-2015 Research Organization for Information Science
+# Copyright (c) 2014-2016 Research Organization for Information Science
 #                         and Technology (RIST). All rights reserved.
 # $COPYRIGHT$
 #
@@ -400,7 +400,7 @@ AC_DEFUN([OPAL_CHECK_EXP_VERBS],[
     AC_DEFINE_UNQUOTED([HAVE_EXP_VERBS], [$have_struct_ibv_exp_send_wr], [Experimental verbs])
     AC_CHECK_DECLS([IBV_EXP_ATOMIC_HCA_REPLY_BE, IBV_EXP_QP_CREATE_ATOMIC_BE_REPLY, ibv_exp_create_qp, ibv_exp_query_device, IBV_EXP_QP_INIT_ATTR_ATOMICS_ARG],
                    [], [], [#include <infiniband/verbs_exp.h>])
-    AC_CHECK_MEMBERS([struct ibv_exp_device_attr.ext_atom, struct ibv_exp_device_attr.ext_atomic_cap], [], [],
+    AC_CHECK_MEMBERS([struct ibv_exp_device_attr.ext_atom, struct ibv_exp_device_attr.exp_atomic_cap], [], [],
                      [[#include <infiniband/verbs_exp.h>]])
     AS_IF([test '$have_struct_ibv_exp_send_wr' = 1], [$1], [$2])
     OPAL_VAR_SCOPE_POP

opal/mca/btl/openib/btl_openib_component.c

@@ -790,7 +790,7 @@ static int init_one_port(opal_list_t *btl_list, mca_btl_openib_device_t *device,
             }
 #endif
 
-#if HAVE_STRUCT_IBV_EXP_DEVICE_ATTR_EXT_ATOMIC_CAP
+#ifdef HAVE_STRUCT_IBV_EXP_DEVICE_ATTR_EXP_ATOMIC_CAP
             switch (openib_btl->device->ib_exp_dev_attr.exp_atomic_cap)
 #else
             switch (openib_btl->device->ib_dev_attr.atomic_cap)