make build fail when need to run gofmt & remove docker pull in travis

use golang 1.8.3 for gateway

Signed-off-by: Minh-Quan TRAN <account@itscaro.me>

.travis.yml

@@ -8,7 +8,6 @@ addons:
       - docker-ce
 
 before_install:
-    - docker pull golang:1.7.5
 
 script:
     - sh build.sh

gateway/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.7.5 as build
+FROM golang:1.8.3 as build
 WORKDIR /go/src/github.com/openfaas/faas/gateway
 
 COPY vendor         vendor

watchdog/Dockerfile

@@ -11,9 +11,9 @@ COPY requesthandler_test.go .
 COPY types types
 
 # Run a gofmt and exclude all vendored code.
-RUN gofmt -l -d $(find . -type f -name '*.go' -not -path "./vendor/*")
+RUN test -z "$(gofmt -l $(find . -type f -name '*.go' -not -path "./vendor/*"))"
 
-RUN go test
+RUN go test -v ./...
 
 # Stripping via -ldflags "-s -w" 
 RUN CGO_ENABLED=0 GOOS=linux go build -a -ldflags "-s -w" -installsuffix cgo -o watchdog . \