qa: stop testing on 16.04 xenial

Note that the hammer old-client test will now *only* run on centos.

Signed-off-by: Sage Weil <sage@redhat.com>

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

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

diff --git a/qa/suites/rados/thrash-old-clients/distro$/ubuntu_16.04.yaml b/qa/suites/rados/thrash-old-clients/distro$/ubuntu_16.04.yaml
deleted file mode 120000 (symlink)
index 053d801..0000000
--- a/qa/suites/rados/thrash-old-clients/distro$/ubuntu_16.04.yaml
+++ /dev/null
@@ -1 +0,0 @@
-.qa/distros/all/ubuntu_16.04.yaml
\ No newline at end of file