LU-8139 ofd: allow brw_size with 'M' suffix

LU-8139 ofd: allow brw_size with 'M' suffix

Allow specifying the 'M' suffix for the obdfilter.*.brw_size tunable
to maintain compatibility with original version of this tunable.

Fix sanity.sh test_101g() to only specify the 'M' suffix if this is
allowed by the server version, otherwise specify only the number.
Check both read and write RPC counts in the test, and also 8MB RPCs.

Clean up test_101g() to remove duplicate code, and only change the
brw_size parameter and remount the clients if the current brw_size
is not large enough.  Calculate the number of pages correctly for
systems with different PAGE_SIZE.

Test-Parameters: trivial envdefinitions=ONLY=101 testlist=sanity,sanity
Test-Parameters: envdefinitions=ONLY=101 testlist=sanity,sanity,sanity
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: If7b268e3ec1160b41a676590a07511a2953ebbe5
Reviewed-on: https://review.whamcloud.com/25335
Reviewed-by: Gu Zheng <gzheng@ddn.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>