docker: fix Docker Hub build failure

Dockerfile

@@ -7,7 +7,7 @@ RUN apk --no-cache --no-progress add --virtual \
 
 WORKDIR /go/src/github.com/gogs/gogs
 COPY . .
-RUN make build TAGS="sqlite cert pam"
+RUN make build-no-gen TAGS="sqlite cert pam"
 
 FROM alpine:3.10
 ADD https://github.com/tianon/gosu/releases/download/1.10/gosu-amd64 /usr/sbin/gosu

Makefile

@@ -38,12 +38,8 @@ govet:
 build: $(GENERATED)
 	go build $(BUILD_FLAGS) -ldflags '$(LDFLAGS)' -tags '$(TAGS)' -trimpath -o gogs
 
-build-dev: $(GENERATED) govet
-	go build $(BUILD_FLAGS) -tags '$(TAGS)' -trimpath -o gogs
-	cp '$(GOPATH)/bin/gogs' .
-
-build-dev-race: $(GENERATED) govet
-	go build $(BUILD_FLAGS) -race -tags '$(TAGS)' -trimpath -o gogs
+build-no-gen:
+	go build $(BUILD_FLAGS) -ldflags '$(LDFLAGS)' -tags '$(TAGS)' -trimpath -o gogs
 
 pack:
 	rm -rf $(RELEASE_GOGS)