travis: Increase travis_wait time while verifying commits
travis: Increase travis_wait time while verifying commits

From https://travis-ci.org/ken2812221/bitcoin-verify-commits/builds
I have run vecify-commits.py nightly on travis, as you can see that 30 minutes is not enough, it took 30-50 minutes to run the script with no extra options. So change it to 50 minutes would be better.

peercoin/peercoin,peercoin/peercoin,DigitalPandacoin/pandacoin,peercoin/peercoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,peercoin/peercoin,peercoin/peercoin,DigitalPandacoin/pandacoin,peercoin/peercoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin