CBLT-312:  export SYNCGATE_PATH, TAP_TIMEOUT earlier, set TIMEOUT to 40000

Change-Id: I22ef4cc53f47c8b699a65a5a6beb87c55a35974e
Reviewed-on: http://review.couchbase.org/38184
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>