Removing memory barriers which are not needed because of

the extra memory barriers which were added in r22880. This 
reverts all of r22879

This commit was SVN r23234.

The following SVN revision numbers were found above:
  r22879 --> open-mpi/ompi@768ea2bab0
  r22880 --> open-mpi/ompi@cd5294944b

ompi/class/ompi_free_list.h

@@ -221,7 +221,6 @@ OMPI_DECLSPEC int ompi_free_list_parse( ompi_free_list_t* list,
         item = (ompi_free_list_item_t*) opal_atomic_lifo_pop(&((fl)->super)); \
         if( OPAL_UNLIKELY(NULL == item) ) rc = OMPI_ERR_TEMP_OUT_OF_RESOURCE; \
     }  \
-    opal_atomic_rmb(); \
 } 
 
 /**
@@ -276,7 +275,6 @@ static inline int __ompi_free_list_wait( ompi_free_list_t* fl,
         OPAL_THREAD_UNLOCK(&((fl)->fl_lock));
         *item = (ompi_free_list_item_t*)opal_atomic_lifo_pop(&((fl)->super));
     }
-    opal_atomic_rmb();
     return OMPI_SUCCESS;
 } 
 
@@ -292,7 +290,6 @@ static inline int __ompi_free_list_wait( ompi_free_list_t* fl,
     do {                                                                \
         opal_list_item_t* original;                                     \
                                                                         \
-	opal_atomic_wmb();                                              \
         original = opal_atomic_lifo_push( &(fl)->super,                 \
                                           &(item)->super);              \
         if( &(fl)->super.opal_lifo_ghost == original ) {                \