LU-687 clio: retry if fault page was truncated

LU-687 clio: retry if fault page was truncated

In vvp_io_fault_start, if a page was truncated we should retry it in
ll_fault() instead of return -EFAULT because it will cause fake OOM.

Change-Id: Ia2ba40ca4ecd67170e6c2eb81ddc0ee34d9379a8
Signed-off-by: Jinshan Xiong <jay@whamcloud.com>
Reviewed-on: http://review.whamcloud.com/1453
Tested-by: Hudson
Reviewed-by: Niu Yawei <niu@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Fan Yong <yong.fan@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>