memcached: mempool parameter is in megabytes, not bytes

Every user of memcached uses bytes for the pool sizing but the server
expects megabytes.

Signed-off-by: Mel Gorman <mgorman@suse.de>
stats: Report 100% reductions where approprite

Signed-off-by: Mel Gorman <mgorman@suse.de>
mmtests: error is not available in run-mmtests.sh context

Signed-off-by: Mel Gorman <mgorman@suse.de>
mmtests: Fix -- processing

Signed-off-by: Mel Gorman <mgorman@suse.de>
mmtests: Report unrecognised options

Signed-off-by: Mel Gorman <mgorman@suse.de>