Fix for the double iWrite problem Edgar found with ROMIO, plus some other

things I found:
  - Locking should prevent it from happening (I think), but there was a 
    race condition in the component progress -- a callback could be
    triggered that would free the request before it was off the outstanding
    requests list.
  - When pulling a request off the component free list, make sure to
    reinitialize the free_called state on the IO request.  This was
    what was causing Edgar's failures
  - In the request cleanup code, pull the request out of the per-
    component free list before returning to the free list.  This
    probably would cause asserts to fire, although it looks like
    I wrote the loops such that it would have been memory safe if
    the asserts didn't fire.  Not really sure why I did that, but
    let's try it again...

This should go to the v1.0 and v1.1 branches.

This commit was SVN r9913.

ompi/mca/io/base/io_base_request.c

@@ -135,6 +135,7 @@ int mca_io_base_request_alloc(ompi_file_t *file,
         if (opal_list_get_size(&file->f_io_requests) > 0) {
             *req = (mca_io_base_request_t*) 
                 opal_list_remove_first(&file->f_io_requests);
+            (*req)->free_called = false;
         } else {
             *req = NULL;
         }
@@ -221,14 +222,11 @@ void mca_io_base_request_free(ompi_file_t *file,
  */
 void mca_io_base_request_return(ompi_file_t *file)
 {
-    opal_list_item_t *p, *next;
+    opal_list_item_t *next;
 
     OPAL_THREAD_LOCK(&file->f_io_requests_lock);
-    for (p = opal_list_get_first(&file->f_io_requests);
-         p != opal_list_get_end(&file->f_io_requests);
-         p = next) {
-        next = opal_list_get_next(p);
-        OMPI_FREE_LIST_RETURN(&mca_io_base_requests, p);
+    while (NULL != (next = opal_list_remove_first(&file->f_io_requests))) {
+        OMPI_FREE_LIST_RETURN(&mca_io_base_requests, next);
     }
     OPAL_THREAD_UNLOCK(&file->f_io_requests_lock);
 }

ompi/mca/io/romio/src/io_romio_component.c

@@ -279,10 +279,10 @@ static int progress()
             return ret;
         } else if (1 == flag) {
             ++count;
-            /* mark as complete (and make sure to wake up any waiters */
-            ompi_request_complete((ompi_request_t*) item);
             /* we're done, so remove us from the pending list */
             opal_list_remove_item(&mca_io_romio_pending_requests, item);
+            /* mark as complete (and make sure to wake up any waiters */
+            ompi_request_complete((ompi_request_t*) item);
             mca_io_base_request_progress_del();
             /* if the request has been freed already, the user isn't
              * going to call test or wait on us, so we need to do it