test: Put new location of magic base tarballs into README.
test: Don't let ipa-server-install block on /dev/random.
test: Allow specification of vlan when adding network interface to a VM.
test: Don't bridge two interfaces on the same network.

This ends in tears without STP enabled.
test: Update README for Fedora 21 support.
test: Remove test-server from SELinux policy and run it unenforced.

The old policy made it fail on Fedora 21 and it doesn't seem to need
any.

However, when enforced, it runs into a timeout of sorts during startup
and the test takes about 30 seconds longer.  So we switch off SELinux
entirely for this one test.