Update .travis.yml to copy the ooniprobe.conf.sample to ooniprobe.conf.
Update .travis.yml to copy the ooniprobe.conf.sample to ooniprobe.conf.

 * Fixes #8450.

0xPoly/ooni-probe,kdmurray91/ooni-probe,kdmurray91/ooni-probe,lordappsec/ooni-probe,0xPoly/ooni-probe,juga0/ooni-probe,0xPoly/ooni-probe,Karthikeyan-kkk/ooni-probe,Karthikeyan-kkk/ooni-probe,lordappsec/ooni-probe,juga0/ooni-probe,juga0/ooni-probe,kdmurray91/ooni-probe,lordappsec/ooni-probe,0xPoly/ooni-probe,kdmurray91/ooni-probe,Karthikeyan-kkk/ooni-probe,Karthikeyan-kkk/ooni-probe,juga0/ooni-probe,lordappsec/ooni-probe