MB-10742 Pass erlang environment flags through OS env variable.

Change-Id: I6020fb38221f24cf9900c8bcedd1cbb32e8ba07d
Reviewed-on: http://review.couchbase.org/35475
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>