MB-8182: Fix OSX statrtup.

Pulled the changes for babysitter vm from linux startup script.

Change-Id: Ifcc09418e7c9817ef2c09283c10cf479a445411e
Reviewed-on: http://review.couchbase.org/26092
Reviewed-by: Sriram Melkote <siri.couchbase@gmail.com>
Tested-by: Ravi Mayuram <ravi@couchbase.com>