Revert "A vendor package now depends on objdb package"

This reverts commit e997e72.

Same change is already in master

Author: chrisplo

Dockerfile

@@ -37,7 +37,6 @@ CMD ["--help"]
 # by far, most of the compilation time is building vendor packages
 # build the vendor dependencies as a separate docker caching layer
 COPY ./vendor/ /go/src/github.com/contiv/netplugin/vendor/
-COPY ./objdb/ /go/src/github.com/contiv/netplugin/objdb/
 
 RUN GOGC=1500 go install -ldflags "-s -w" $(go list ./vendor/...)