Exclude paas for centos-7 mirror

This folder was added recently, which didn't exist in our original
exclude script.

Change-Id: Ieb59d5bdc84500fd84d1aa3420c5ef81219f726c
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

modules/openstack_project/files/mirror/centos-mirror-update.sh

@@ -34,6 +34,7 @@ $K5START rsync -rlptDvz \
     --exclude="cr" \
     --exclude="fasttrack" \
     --exclude="isos" \
+    --exclude="paas" \
     --exclude="sclo" \
     --exclude="storage" \
     --exclude="virt" \