glusterd: Removed fd leaks in glusterfs_start utility function

PROBLEM:
    The FILE* associated with the pidfile was leaked if
    pmap_registry_search on the brickinfo' path failed.

FIX:
    Eliminates the use of the FILE* that was leaked. Uses
    glusterd_is_service_running utility function in place
    of the earlier attempt to check for the same.

Change-Id: I94082bd5a94b8a6340f8cc11726d3264e364efe6
BUG: 916549
Signed-off-by: Krishnan Parthasarathi <kparthas@redhat.com>
Reviewed-on: http://review.gluster.org/4596
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
Reviewed-by: Anand Avati <avati@redhat.com>