RHEL 7: Remove User-Mode Linux (RHBZ#1144197).

This isn't supported in RHEL 7.
RHEL 7: v2v: Select correct qemu binary for -o qemu mode (RHBZ#1147313).

RHEL 7 does not have qemu-system-x86_64 (etc), and in addition the
qemu binary is located in /usr/libexec.  Encode the path to this
binary directly in the script.

Note that we don't support people running qemu directly like this.
It's just for quick testing of converted VMs, and to help us with
support cases.
RHEL 7: v2v: Disable the --qemu-boot option (RHBZ#1147313).

This cannot work because there is no Gtk or SDL output mode
in RHEL 7's qemu-kvm.

In addition you will have to edit the -display option in the
qemu script.
RHEL 7: Revert "tests: rsync: Skip this test when the backend is libvirt."

This reverts commit 765dc6237ce7b93dd2f33d99be53eae92e048a7a.
RHEL 7: Revert "appliance: Change example ping lines to ping 8.8.8.8."

This reverts commit 07c0926b588db5c86214917b609c2f477c817c0e.
RHEL 7: Revert "launch: libvirt: Use qemu-bridge-helper to implement a full network (RHBZ#1148012)."

This reverts commit 224de20b9a8d5ea56f6337f19b4ca237bb88eca0.
RHEL 7: Revert "appliance: add dhcp-client on Mageia"

This reverts commit 8f3a2ca5358d5601be7a9247b6d08193c4e2da46.
RHEL 7: Revert "appliance: add dhcpcd and gptfdisk on Archlinux"

This reverts commit 979e7a49147f4ef1387337db262bf7ea12f627e3.
RHEL 7: Revert "appliance: Use dhclient or dhcpcd instead of hard-coding IP address of appliance."

This reverts commit 67e6f32a240c7c234e6af637c1cd324b36a82cd3.
RHEL 7: v2v: Disable unconfiguration of VMware drivers on Linux (RHBZ#1155610).

This is currently broken and breaks conversions.  For details see:
https://bugzilla.redhat.com/show_bug.cgi?id=1155610
RHEL 7: Disable alternate Augeas lenses.

These are included in the RHEL 7.1 augeas package, and therefore
not required in RHEL.

See:
https://www.redhat.com/archives/libguestfs/2014-October/msg00220.html