ORNL-24 skip unnecessary client obj hash lookup

ORNL-24 skip unnecessary client obj hash lookup

The client-side object will be initialized when inode is established
in memory. Such object will be inserted into global hash table for
further using. The caller follows "lookup-alloc-lookup-insert". It is
standard, but maybe unnecessary for some cases. If it is sure that
there is only one caller will insert the new established object, then
we can skip the two lookup, and "alloc-insert" directly.

Signed-off-by: Fan Yong <yong.fan@whamcloud.com>
Change-Id: Ie173c57627b2e5b4ed9b8a93f368d88ba8e54c31
Reviewed-on: http://review.whamcloud.com/1225
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Jinshan Xiong <jay@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>