Finish Travis build as soon as a single job failed.
Finish Travis build as soon as a single job failed.

Manually cancelling obviously failing builds is getting cumbersome.
Hopefully this will speed things up as a side effect.

References:
- https://docs.travis-ci.com/user/customizing-the-build/#Fast-Finishing

frodrigo/osrm-backend,beemogmbh/osrm-backend,arnekaiser/osrm-backend,raymond0/osrm-backend,arnekaiser/osrm-backend,hydrays/osrm-backend,KnockSoftware/osrm-backend,duizendnegen/osrm-backend,neilbu/osrm-backend,duizendnegen/osrm-backend,oxidase/osrm-backend,Project-OSRM/osrm-backend,hydrays/osrm-backend,duizendnegen/osrm-backend,felixguendling/osrm-backend,bjtaylor1/osrm-backend,beemogmbh/osrm-backend,deniskoronchik/osrm-backend,hydrays/osrm-backend,bjtaylor1/osrm-backend,yuryleb/osrm-backend,deniskoronchik/osrm-backend,arnekaiser/osrm-backend,deniskoronchik/osrm-backend,Project-OSRM/osrm-backend,frodrigo/osrm-backend,yuryleb/osrm-backend,oxidase/osrm-backend,beemogmbh/osrm-backend,deniskoronchik/osrm-backend,yuryleb/osrm-backend,bjtaylor1/osrm-backend,oxidase/osrm-backend,yuryleb/osrm-backend,bjtaylor1/osrm-backend,hydrays/osrm-backend,duizendnegen/osrm-backend,Project-OSRM/osrm-backend,frodrigo/osrm-backend,frodrigo/osrm-backend,Project-OSRM/osrm-backend,raymond0/osrm-backend,neilbu/osrm-backend,beemogmbh/osrm-backend,felixguendling/osrm-backend,felixguendling/osrm-backend,oxidase/osrm-backend,neilbu/osrm-backend,raymond0/osrm-backend,KnockSoftware/osrm-backend,arnekaiser/osrm-backend,KnockSoftware/osrm-backend,KnockSoftware/osrm-backend,raymond0/osrm-backend,neilbu/osrm-backend