LU-1329 ptlrpc: handle -EINPROGRESS for create

LU-1329 ptlrpc: handle -EINPROGRESS for create

If some metadata operation get -EINPROGRESS from server, client
should retry the operation infinitely. Which is required by
the new quota design in the DNE environment.

We handle -EINPROGRESS only for create operation for now, if
necessary, it can be extended for other operations later.

Signed-off-by: Niu Yawei <niu@whamcloud.com>
Change-Id: Iad568afeff0af1d4df840d3acf2df161df6f7690
Reviewed-on: http://review.whamcloud.com/2572
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Johann Lombardi <johann@whamcloud.com>
Reviewed-by: Fan Yong <yong.fan@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>