[VDSM] Add Travis CI to vdsm github project

[Nir Soffer]

Hi all,

Vdsm includes now a travis configuration running vdsm tests
on both Fedora 24 and Centos 7.

You can see example build shere:
https://travis-ci.org/nirs/vdsm/builds/166263228

These builds are currently configured in my private vdsm
fork on github.

We want to enable Travis CI service on vdsm github project,
so each time a patch is merged (sync from gerrit) or each time
a pull request is submitted, a build is started.

Developers can use these builds in 2 ways:
- fork vdsm and enable travis on their fork
- submit pull requests to get them tested

When a build fails, travis sends email to the author about the
failure, this works fine for developers forks without any
additional configuration.

You can configure github for us, or give Dan and/or me the
permissions to configure the github project.

Cheers,
Nir