travis: Don't run 'make lint' twice.
travis: Don't run 'make lint' twice.

'make lint' takes up a lot of resources and is very slow.
Currently we are running it twice for each environment.
Avoid it.

Signed-off-by: Gurucharan Shetty <a1872e333d0e52644f6125da2276530f7ebe5e77@ovn.org>

shettyg/ovn-kubernetes,shettyg/ovn-kubernetes,shettyg/ovn-kubernetes