LU-8683 readahead: update ras window correctly

LU-8683 readahead: 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.

Lustre-change: http://review.whamcloud.com/17343
Lustre-commit: 88ef5af0bed93c88984c226db755d07601aef60f

Signed-off-by: Bobi Jam <bobijam.xu@intel.com>
Change-Id: Iba6e51f12ac4d00548cc99b7bd423502b754db13
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Reviewed-on: http://review.whamcloud.com/23032
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: wangdi <di.wang@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>