LU-8413 test: limit # of processes for sanity test_101f

LU-8413 test: limit # of processes for sanity test_101f

It tries to test mmap readahead does not miss too much pages,
so we need limit the number of processes of the iozone read.

Test-Parameters: trivial
Signed-off-by: Bobi Jam <bobijam.xu@intel.com>
Change-Id: Ic5c753549234fe2bffcaa42f75208c2295f84ac0
Reviewed-on: http://review.whamcloud.com/23039
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Nunez <james.a.nunez@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>