staging/lustre: remove enum config_flags and obd_mount_server.c

obd_mount_server.c is not really used at all, and we can remove
enum config_flags that are causing symbol conflictions due to
CONFIG_ prefixing...

Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>