federatedx: avoid unnecessary bzero. improve dbug traces

storage/federatedx/ha_federatedx.cc

@@ -2732,7 +2732,8 @@ int ha_federatedx::read_range_next()
 int ha_federatedx::index_next(uchar *buf)
 {
   DBUG_ENTER("ha_federatedx::index_next");
-  DBUG_RETURN(read_next(buf, stored_result));
+  int retval=read_next(buf, stored_result);
+  DBUG_RETURN(retval);
 }
 
 
@@ -2887,7 +2888,8 @@ int ha_federatedx::rnd_next(uchar *buf)
     */
     DBUG_RETURN(1);
   }
-  DBUG_RETURN(read_next(buf, stored_result));
+  int retval=read_next(buf, stored_result);
+  DBUG_RETURN(retval);
 }
 
 
@@ -2958,10 +2960,11 @@ void ha_federatedx::position(const uchar *record __attribute__ ((unused)))
 {
   DBUG_ENTER("ha_federatedx::position");
 
-  bzero(ref, ref_length);
-
   if (!stored_result)
+  {
+    bzero(ref, ref_length);
     DBUG_VOID_RETURN;
+  }
 
   if (txn->acquire(share, TRUE, &io))
     DBUG_VOID_RETURN;