Migrate to built-in Go vendoring.

This also removes `godep` calls from make scripts. Of note is that
currently `./...` checking in acceptance tests is disabled.

scripts/coverage.sh

@@ -38,7 +38,7 @@ push_to_coveralls() {
     goveralls -coverprofile="$profile"
 }
 
-generate_cover_data $(go list ./...)
+generate_cover_data $(go list ./... | grep -v /vendor/)
 show_cover_report func
 case "$1" in
 "")