LU-1330 obdclass: split client-server mount routines

Move server side mount routines to obd_mount_server.c.  Const correct
several server_name2xxx type functions.

Signed-off-by: Liu Xuezhao <xuezhao.liu@emc.com>
Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I8abdb6fdd0411f2e75f6fb6ee4ff8502e50ef213
Reviewed-on: http://review.whamcloud.com/2672
Tested-by: Hudson
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Peng Tao <bergwolf@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>