Use current ODL Integration/Test repo

Use current ODL Integration/Test repo

ODL Integration used to contain system testing, Karaf distribution
building and packaging/delivery logic. It was split into three
projects in August 2015: Int/Test, Int/Distribution and Int/Packaging.

https://wiki.opendaylight.org/view/Archive_Proposals/Integration

The integration.git repo Functest was cloning is the old one,
containing all three projects. It hasn't been updated since the split.

The new integration-test.git repo is the current version of ODL's system
test code.

This change also clones ODL from its official Gerrit, instead of its
GitHub mirror.

Change-Id: I6b38b1fedada504411ca0e0639355339f373084c
Signed-off-by: Daniel Farrell <dfarrell@redhat.com>