CBLT-41: Build sync gateway out of stable branch

Change-Id: I0ad73369772d9c8cabe03c476d05b7c07bb76d31
Reviewed-on: http://review.couchbase.org/28886
Reviewed-by: Bin Cui <bin.cui@gmail.com>
Tested-by: Bin Cui <bin.cui@gmail.com>