usnic: EHOSTUNREACH means there is no route

ibv_create_ah() can also return EHOSTUNREACH, which means that there
is no route to the peer.  Treat that as a non-fatal warning.

Reviewed by Reese Faucette.

cmr=v1.8.2:reviewer=ompi-rm1.8

This commit was SVN r32135.

ompi/mca/btl/usnic/btl_usnic_module.c

@@ -260,7 +260,8 @@ static int add_procs_create_ahs(ompi_btl_usnic_module_t *module,
                    (e.g., the networking is hosed between us).  So
                    just mark that we can't reach this peer, and print
                    a pretty warning. */
-                else if (EADDRNOTAVAIL == errno) {
+                else if (EADDRNOTAVAIL == errno ||
+                         EHOSTUNREACH == errno) {
                     add_procs_warn_ah_fail(module, endpoints[i]);
 
                     OBJ_RELEASE(endpoints[i]);