Fix a subtle bug in the convertor where the lb of the datatype

can be added twice (for partially packed datatypes). Thanks to
the Fujitsu's MPI development team for the bug report and the
patch.

opal/datatype/opal_convertor.c

@@ -3,7 +3,7 @@
  * Copyright (c) 2004-2006 The Trustees of Indiana University and Indiana
  *                         University Research and Technology
  *                         Corporation.  All rights reserved.
- * Copyright (c) 2004-2013 The University of Tennessee and The University
+ * Copyright (c) 2004-2014 The University of Tennessee and The University
  *                         of Tennessee Research Foundation.  All rights
  *                         reserved.
  * Copyright (c) 2004-2006 High Performance Computing Center Stuttgart,
@@ -362,11 +362,11 @@ static inline int opal_convertor_create_stack_with_pos_contig( opal_convertor_t*
     if( OPAL_LIKELY(0 == count) ) {
         pStack[1].type     = pElems->elem.common.type;
         pStack[1].count    = pElems->elem.count;
-        pStack[1].disp     = pElems->elem.disp;
+        pStack[1].disp     = 0;
     } else {
         pStack[1].type  = OPAL_DATATYPE_UINT1;
         pStack[1].count = pData->size - count;
-        pStack[1].disp  = pData->true_lb + count;
+        pStack[1].disp  = count;
     }
     pStack[1].index    = 0;  /* useless */