qa/tests: added missed ubuntu_latest

Signed-off-by: Yuri Weinstein <yweinste@redhat.com>

diff --git a/qa/distros/supported/ubuntu_latest.yaml b/qa/distros/supported/ubuntu_latest.yaml
new file mode 120000 (symlink)
index 0000000..69ebbd4
--- /dev/null
+++ b/qa/distros/supported/ubuntu_latest.yaml
@@ -0,0 +1 @@
+../all/ubuntu_16.04.yaml
\ No newline at end of file