travis.yml: Fix keywords

All the documentation on travis-ci.com talks about "jobs:" instead of
"matrix:" these days, so let's also use this keywords now. Also fix
a typo in "inlcude" - it's weird that Travis did not complain about
this, but it's certainly better to have this fixed.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>