Use gometalinter for linting

gometalinter runs linters in parallel for faster linting
it provides a uniform way of whitelisting lines using // nolint or the exclude
field in the config

Signed-off-by: Daniel Nephin <dnephin@gmail.com>

mount/mount_unix.go

@@ -5,17 +5,21 @@ package mount
 import "github.com/pkg/errors"
 
 var (
+	// ErrNotImplementOnUnix is returned for methods that are not implemented
 	ErrNotImplementOnUnix = errors.New("not implemented under unix")
 )
 
+// Mount is not implemented on this platform
 func (m *Mount) Mount(target string) error {
 	return ErrNotImplementOnUnix
 }
 
+// Unmount is not implemented on this platform
 func Unmount(mount string, flags int) error {
 	return ErrNotImplementOnUnix
 }
 
+// UnmountAll is not implemented on this platform
 func UnmountAll(mount string, flags int) error {
 	return ErrNotImplementOnUnix
 }