Show capital -P flag for password in mctimings usage

Change-Id: I828cb62e84af149abb71b13df597b02a14426f7b
Reviewed-on: http://review.couchbase.org/36107
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>