LU-8857 config: refactor sptlrpc config process

LU-8857 config: refactor sptlrpc config process

MDT/OFD may access config llog directly, e.g. accessing sptlrpc
local copy, but this config context is not initialized, these code
existed before, but maybe got lost in server code refactor before.
But after reviewing code this is not necessary, target doesn't
need to access sptlrpc config directly, but leave it the same as
other configs, that is, let MGC to handle.

Besides, ofd_set_info_hdl() doesn't need to handle KEY_SPTLRPC_CONF
because this key is handled in o_set_info_async only.

As a side effect, remove obsolete function lustre_rename().

Signed-off-by: Lai Siyao <lai.siyao@intel.com>
Change-Id: If0937cf6e5e03bc84f883131bbf63326e847e701
Reviewed-on: https://review.whamcloud.com/24119
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>