Merge pull request #430 from ggouaillardet/issue/404

romio: always set err_ status in MPIO_DATATYPE_ISCOMMITTED

ompi/mca/io/romio/romio/mpi-io/mpioimpl.h

@@ -36,7 +36,7 @@
    of correct programs */
 #define MPIU_THREAD_CS_ENTER(x,y)
 #define MPIU_THREAD_CS_EXIT(x,y)
-#define MPIO_DATATYPE_ISCOMMITTED(dtype_, err_) do {} while (0)
+#define MPIO_DATATYPE_ISCOMMITTED(dtype_, err_) do { err_ = 0; } while (0)
 #ifdef HAVE_WINDOWS_H
 #define MPIU_UNREFERENCED_ARG(a) a
 #else