build(go): enable static analysis of go code

- Add go bin path to build stage for staticcheck tool
- Remove unneeded double go mod download and GO111MODULE env var

Dockerfile

@@ -130,7 +130,6 @@ USER ${build_user}
 
 # Install golang module dependencies before copying source to cache them in their own layer
 WORKDIR /go/src/github.com/controlplaneio/simulator-standalone
-RUN go mod download
 
 # Add the full source tree
 COPY --chown=1000 .  /go/src/github.com/controlplaneio/simulator-standalone/
@@ -140,11 +139,14 @@ WORKDIR /go/src/github.com/controlplaneio/simulator-standalone/
 USER root
 RUN chown -R ${build_user}:${build_user} /go/src/github.com/controlplaneio/simulator-standalone/
 
+RUN go get honnef.co/go/tools/cmd/staticcheck
 USER ${build_user}
 
+RUN mkdir /home/${build_user}/go/bin
+ENV PATH=${PATH}:/home/${build_user}/go/bin
+
 # Golang build and test
 WORKDIR /go/src/github.com/controlplaneio/simulator-standalone
-ENV GO111MODULE=on
 RUN make test-unit
 
 #------------------#

Makefile

@@ -111,16 +111,16 @@ docker-test: validate-reqs docker-build ## Run the tests
 # -- SIMULATOR CLI
 .PHONY: dep
 dep: ## Install dependencies for other targets
-	$(GO) mod download 2>&1
+	$(GO) mod download
 	$(GO) get honnef.co/go/tools/cmd/staticcheck
 
 .PHONY: static-analysis
-static-analysis:
-	#$(GO) vet
+static-analysis: dep
+	$(GO) vet
 	staticcheck $(PKG)
 
 .PHONY: build
-build: dep ## Run golang build for the CLI program
+build: static-analysis ## Run golang build for the CLI program
 	@echo "+ $@"
 	$(GO) build ${GO_LDFLAGS} -a -o ./dist/simulator