travis: fix some travis warnings
travis: fix some travis warnings

root: deprecated key sudo (The key `sudo` has no effect anymore.)
root: missing os, using the default linux
root: key matrix is an alias for jobs, using jobs

Signed-off-by: Tycho Andersen <6b523322678240882acbb4da5312a12d8cd0082d@tycho.ws>

zordsdavini/qtile,zordsdavini/qtile