Fix a deadlock in the put protocol for MX. The callback was never triggered,

as the send and the put share the same execution path and in the case of the
put the MCA_BTL_DES_SEND_ALWAYS_CALLBACK was not set.

This commit was SVN r18735.

ompi/mca/btl/mx/btl_mx.c

@@ -376,8 +376,9 @@ static int mca_btl_mx_put( struct mca_btl_base_module_t* btl,
             return OMPI_ERROR;
     }
 
-    frag->endpoint  = endpoint;
-    frag->type      = MCA_BTL_MX_SEND;
+    frag->endpoint         = endpoint;
+    frag->type             = MCA_BTL_MX_SEND;
+    descriptor->des_flags |= MCA_BTL_DES_SEND_ALWAYS_CALLBACK;
 
     do {
         mx_segment[i].segment_ptr    = descriptor->des_src[i].seg_addr.pval;
@@ -453,6 +454,7 @@ int mca_btl_mx_send( struct mca_btl_base_module_t* btl,
         if( OPAL_UNLIKELY(MX_SUCCESS != mx_return) ) {
             opal_output( 0, "mx_ibuffered failed with error %d (%s)\n",
                          mx_return, mx_strerror(mx_return) );
+            frag->base.des_flags |= MCA_BTL_DES_SEND_ALWAYS_CALLBACK;
             return OMPI_ERROR;
         }
         if( mx_result ) {
@@ -475,7 +477,7 @@ int mca_btl_mx_send( struct mca_btl_base_module_t* btl,
         }
     }
 #endif
-    if( 4096 > total_length ) {
+    if( 2048 > total_length ) {
         mx_status_t mx_status;
         uint32_t mx_result;