Separate build functional tests from Makefile (#6351)

Recently travis seems to have issues with builds after
merge, so this PR is an experiment to fix this.

Failed: https://travis-ci.org/minio/minio/builds/419769285#L2310

Succeeded: https://travis-ci.org/minio/minio/builds/419565606#L2322

This PR was tested to be working properly on my fork to build
on travis, would need to do the same in minio/minio and see
how it goes through.

.travis.yml

@@ -20,14 +20,14 @@ matrix:
     - os: linux
       env:
         - ARCH=x86_64
-      go: 1.10.1
+      go: 1.10.3
       script:
         - make
         - diff -au <(gofmt -s -d cmd) <(printf "")
         - diff -au <(gofmt -s -d pkg) <(printf "")
         - make test GOFLAGS="-timeout 15m -race -v"
+        - make verify
         - make coverage
-        - node --version
         - cd browser && yarn && yarn test && cd ..
 
 before_install:

Makefile

@@ -61,6 +61,8 @@ check: test
 test: verifiers build
 	@echo "Running unit tests"
 	@go test $(GOFLAGS) -tags kqueue ./...
+
+verify: build
 	@echo "Verifying build"
 	@(env bash $(PWD)/buildscripts/verify-build.sh)