LU-6846 llog: create remote llog synchronously

LU-6846 llog: create remote llog synchronously

Create remote llog synchronously, because llog_create
for remote object only pack the RPC in the buffer,
instead the real llog object will be created until
transaction stop. If other thread happens to use
this llog object and send RPC before the creation,
which might cause the failure.

Signed-off-by: wang di <di.wang@intel.com>
Change-Id: I6c806174381b87836b1f6dd833cda50f0ab2d168
Reviewed-on: http://review.whamcloud.com/16333
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>