Building with Go 1.12 fails with "go tool vet" directly is unsupported; use "go vet"

[k-wall]

As noted in Go's release notes, go tool vet is no longer supported

cd /Users/keith/src/forks/enmasse/go/src/github.com/enmasseproject/enmasse && go tool vet cmd pkg
vet: invoking "go tool vet" directly is unsupported; use "go vet"
make[1]: *** [test_go_vet] Error 1

We want to keep compatibility with Go 1.10 and Go 1.11 so we need the build system to work with all three.

It appears with Go 1.12 the vet arguments are different. It appear to scan for packages and finds system libraries.

cd /Users/keith/src/forks/enmasse/go/src/github.com/enmasseproject/enmasse && go vet cmd
# cmd/internal/bio
/usr/local/Cellar/go/1.12/libexec/src/cmd/internal/bio/buf.go:45:18: method Seek(offset int64, whence int) int64 should have signature Seek(int64, int) (int64, error)
/usr/local/Cellar/go/1.12/libexec/src/cmd/internal/bio/buf.go:57:18: method Seek(offset int64, whence int) int64 should have signature Seek(int64, int) (int64, error)
# cmd/link
/usr/local/Cellar/go/1.12/libexec/src/cmd/link/link_test.go:15:2: struct field tag "\n\tLondon. Michaelmas term lately over, and the Lord Chancellor sitting in Lincoln�s Inn Hall. Imp

[ctron]

I can run go vet with Go 1.11.2 … And I think we could get away focusing on Go 1.11.x

[jbtrystram]

I just ran into this as well : looks like Go 1.12 is default in fedora 30.

Also, Go vet is not happy with the pkg argument :

[enmasse] cd /home/jbtrystram/go/src/github.com/enmasseproject/enmasse/go/src/github.com/enmasseproject/enmasse && go vet pkg
can't load package: package pkg: cannot find package "pkg" in any of:
	/usr/lib/golang/src/pkg (from $GOROOT)
	/home/jbtrystram/go/src/pkg (from $GOPATH)

[secondsun]

@jbtrystram go vet ./pkg/... makes it happy

[secondsun]

PR with fix : #2951