Change linter from gometalinter to golangci-lint

[ShyamsundarR]

Describe the bug
gometalinter is being deprecated in favor of golangci-lint (see, alecthomas/gometalinter#590).

We possibly need to move make test and the TravisCI job to the newer linter.

[Madhu-1]

@ShyamsundarR @rootfs can we close this one?