test: check-journal for Fedora 21

Log in as root...
test: check-multi-machine and check-dashboard for buggy Fedora 21
test: Disable check-storage testDosParts

And don't use extended partitions in other tests.

See https://bugzilla.redhat.com/show_bug.cgi?id=1135493
test: Work around freeipa-client bug in Fedora 21
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: Only build selinux-policy for Fedora 20.

Installing it on Fedora 21 fails.
test: Update README for Fedora 21 support.