travis: use 'git fetch' to deepen, not 'git pull'
authorBrian Warner <warner@lothar.com>
Tue, 22 Sep 2015 19:10:15 +0000 (12:10 -0700)
committerBrian Warner <warner@lothar.com>
Tue, 22 Sep 2015 19:10:15 +0000 (12:10 -0700)
commit759e87b24bec548677e8b36015341472fea0e858
tree0b5cc2ffa063252bcb8cdd1cfdc7839aba1df898
parenta4dfc31a19afd39c27120fac0588250a1f5f48e9
travis: use 'git fetch' to deepen, not 'git pull'

Travis builds of branches (i.e. pull-requests) were testing the wrong
thing, because the 'git pull' was causing current trunk to be
auto-merged. At least that's what seemed to break
https://travis-ci.org/tahoe-lafs/tahoe-lafs/jobs/81517826 : it hung
forever waiting for a commit message to be entered.

Also add "sudo: false" to use travis containers (faster) instead of new
VMs. We only use pip to install dependencies, not apt, so we don't need
root.
.travis.yml