romio: Fix wrong communicator use in ADIOI_GEN_OpenColl

When ADIOI_GEN_OpenColl is called in ADIO_CREAT mode,
file creation is done by calling ADIOI_xxx_Open with
MPI_COMM_SELF by rank == fd->hints->ranklist[0].
If successful, the file is closed with ADIOI_xxx_Close,
and later the file will be opened by all without creation flag.

The problem is that the communicator of ADIOI_GEN_OpenColl
is passed to ADIOI_xxx_Close instead of MPI_COMM_SELF.
If a collective call is made using this communicator
in ADIOI_xxx_Close, it may hang.

src/mpi/romio/adio/common/ad_opencoll.c

@@ -80,11 +80,11 @@ void ADIOI_GEN_OpenColl(ADIO_File fd, int rank, int access_mode, int *error_code
  tmp_comm = fd->comm;
  fd->comm = MPI_COMM_SELF;
  (*(fd->fns->ADIOI_xxx_Open)) (fd, error_code);
- fd->comm = tmp_comm;
- MPI_Bcast(error_code, 1, MPI_INT, fd->hints->ranklist[0], fd->comm);
+ MPI_Bcast(error_code, 1, MPI_INT, fd->hints->ranklist[0], tmp_comm);
  /* if no error, close the file and reopen normally below */
  if (*error_code == MPI_SUCCESS)
  (*(fd->fns->ADIOI_xxx_Close)) (fd, error_code);
+ fd->comm = tmp_comm;
 
  fd->access_mode = access_mode; /* back to original */
  } else