Revert "Update to using pike cloud-archive"

This reverts commit a7e9a5d.

The jobs that run live migration tests are failing at about
a rate of 50% since this merged. There are no recent changes
to nova in the last 24 hours that are related to live
migration, and this is failing on the master branch only,
so I suspect the failures are due to new qemu packages
getting pulled in from this change.

Change-Id: Ic8481539c6a0cc7af08a736a625b672979435908
Closes-Bug: #1718295

tools/fixup_stuff.sh

@@ -84,10 +84,10 @@ if [[ "${ENABLE_UBUNTU_CLOUD_ARCHIVE}" == "True" && "$DISTRO" = "xenial" ]]; the
         # we can find local mirrors then use that mirror.
         source /etc/ci/mirror_info.sh
 
-        sudo apt-add-repository -y "deb $NODEPOOL_UCA_MIRROR xenial-updates/pike main"
+        sudo apt-add-repository -y "deb $NODEPOOL_UCA_MIRROR xenial-updates/ocata main"
     else
         # Otherwise use upstream UCA
-        sudo add-apt-repository -y cloud-archive:pike
+        sudo add-apt-repository -y cloud-archive:ocata
     fi
 
     # Disable use of libvirt wheel since a cached wheel build might be