Enable golint in travis and Makefile

.travis.yml

@@ -1,4 +1,7 @@
 sudo: required
+language: go
+dist:     trusty
+
 services:
   - docker
 
@@ -21,6 +24,12 @@ before_install: |
     exit 1
   fi
 
+before_script:
+  - go get golang.org/x/lint/golint
+
 # cephfs (fuse) requires: --device /dev/fuse --cap-add SYS_ADMIN --security-opt apparmor:unconfined
 script:
   - docker run --device /dev/fuse --cap-add SYS_ADMIN --security-opt apparmor:unconfined --rm -it -v ${PWD}:/go/src/github.com/ceph/go-ceph:z ceph-golang-ci
+# run golint and other style checks
+  - go get golang.org/x/lint/golint
+  - make check

Makefile

@@ -12,3 +12,7 @@ test-docker: .build-docker
 .build-docker:
 	docker build -t $(DOCKER_CI_IMAGE) .
 	@docker inspect -f '{{.Id}}' $(DOCKER_CI_IMAGE) > .build-docker
+
+check:
+	# TODO: add this when golint is fixed	@for d in $$(go list ./... | grep -v /vendor/); do golint -set_exit_status $${d}; done
+	@for d in $$(go list ./... | grep -v /vendor/); do golint $${d}; done