qa/rgw: pacific upgrade disables centos9

we don't build centos 9 packages for pacific, so the pacific upgrade
suite was failing with errors like:

Failed to fetch package version from https://shaman.ceph.com/api/search/?status=ready&project=ceph&flavor=default&distros=centos%2F9%2Fx86_64&ref=pacific

Fixes: https://tracker.ceph.com/issues/62135
Signed-off-by: Casey Bodley <cbodley@redhat.com>

diff --git a/qa/suites/rgw/upgrade/1-install/pacific/distro$/centos_8.stream.yaml b/qa/suites/rgw/upgrade/1-install/pacific/distro$/centos_8.stream.yaml
new file mode 120000 (symlink)
index 0000000..5dceec7
--- /dev/null
+++ b/qa/suites/rgw/upgrade/1-install/pacific/distro$/centos_8.stream.yaml
@@ -0,0 +1 @@
+.qa/distros/supported/centos_8.stream.yaml
\ No newline at end of file

diff --git a/qa/suites/rgw/upgrade/1-install/pacific/distro$/centos_latest.yaml b/qa/suites/rgw/upgrade/1-install/pacific/distro$/centos_latest.yaml
deleted file mode 120000 (symlink)
index bd9854e..0000000
--- a/qa/suites/rgw/upgrade/1-install/pacific/distro$/centos_latest.yaml
+++ /dev/null
@@ -1 +0,0 @@
-.qa/distros/supported/centos_latest.yaml
\ No newline at end of file