Remove option -m to set max size

This option should be set using cache_size= instead

Change-Id: Ia72ed1562d3628fcdac91d54dc59774e29d5a320
Reviewed-on: http://review.couchbase.org/33082
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>