staging/lustre/llite: update ras window correctly

When stride-RA hit case miss, we only reset normal sequential
read-ahead window, but not reset the stride IO to avoid the overhead
of re-detecting stride IO. While when the normal RA window is set
to not insect with the stride-RA window, when we try to increase
the stride-RA window length later, the presumption does not hold.

This patch resets the stride IO as well in this case.

Signed-off-by: Bobi Jam <bobijam.xu@intel.com>
Reviewed-on: http://review.whamcloud.com/23032
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-8683


Reviewed-by: wangdi <di.wang@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>