MB-12361: do not use server header for send_no_active_vbuckets

This is de-facto backport of http://review.couchbase.org/36739.

Change-Id: Ie45730d867e50772866eb8d14411d670828190a0
Reviewed-on: http://review.couchbase.org/42176
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>