New version of Mock (kind of)

[Miroslav Suchý]

I just tagged new version in Mock.git. But I will not release it.

There are several changes:
 * version bumped up to 1.3.1
 * move /usr/sbin/mock to /usr/libexec/mock/mock [RHBZ#1246810]
   This needs a lot of testing. On RHEL7 you will need to set SELinux to permissive (until RHEL 7.4 is out).
 * F22 configs has been removed
 * I set up Copr project:
     https://copr.fedorainfracloud.org/coprs/g/mock/mock/
   After each commit in devel branch, there will be git snapshot build.
 * I removed the automake and it will use Tito now. If you are new to tito, then just:
     sudo dnf install tito
     tito build --rpm --test -i  # install code from last commit
     tito build --rpm # build latest tagged version
   The benefits are that release process is now *much* easier. And there are no more build artefacts directly in git repo.

Those changes are huge. So I'm *not* going to push it to Fedora. Not even to rawhide. Please test it and report any issues.