MB-11406: don't use infinity shutdown timeout for R14 compat

R14's supervisor indeed doesn't support infinity for shutdown timeout
of non-supervisor-type childs. We just give it large value.

Change-Id: Id847ca6b3f73663a06d48d8b07ea1fef7357d5b8
Reviewed-on: http://review.couchbase.org/38983
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>