CBD-1438: Different handling for Go binary renaming

Ensure that Go binaries are renamed immediately after building, to
avoid being stomped by other projects with the same basename. This
partially defeats Go's incremental build abilities, but is
unavoidable.

Change-Id: Ib5b48d0e47862f3c8cfe612adb296e334eba5dc4
Reviewed-on: http://review.couchbase.org/42386
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>