Cleanup testrepository leftover files

Data from previous runs piles up and eats up disk space (neutron had
7G). So the data of the current run is kept for debuggability.
Put someone's fiddling in git

Combination filter changed in the web interface.
Remove many client unit tests

The following list of clients now run unit tests during RPM build:

    python-designateclient
    python-ironicclient
    python-marconiclient
    python-openstackclient
    python-troveclient
    python-tuskarclient

This already revealed several issues.