Disable the homebrew check for v8

Change-Id: I1c1a832998d7d829d9415ed5ae67f3f6e8c305bb
Reviewed-on: http://review.couchbase.org/30671
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>