Merge ~txiao/charm-nrpe:func-fix into charm-nrpe:master

[Tianqi Xiao]

Fix functional test by specifying a different channel for rabbitmq-server in xenial bundle

Xenial is not a supporting series in rabbitmq-server's default channel (3.9/stable). Specifying a different channel, 3.6/edge, for this charm to resolve functional test errors.

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[🤖 prod-jenkaas-bootstack (prod-jenkaas-bootstack)]

PASSED: Continuous integration, rev:36de66cadbaa2e4989307e07b97412d8576e1d10
https://jenkins.canonical.com/bootstack/job/lp-charm-nrpe-ci/61/
Executed test runs:
    SUCCESS: https://jenkins.canonical.com/bootstack/job/lp-charm-test-functest/1806/
    None: https://jenkins.canonical.com/bootstack/job/lp-update-mp/519/

Click here to trigger a rebuild:
https://jenkins.canonical.com/bootstack/job/lp-charm-nrpe-ci/61//rebuild

review: Approve (continuous-integration)

[Erhan Sunar (esunar)]

Since there is no stable charm for xenial, LGTM

review: Approve

[Robert Gildein (rgildein)]

review: Approve

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Change successfully merged at revision b2b029a74e49e5e54735fce1efc00ba592854f17

diff --git a/tests/functional/tests/bundles/overlays/xenial.yaml.j2 b/tests/functional/tests/bundles/overlays/xenial.yaml.j2
index 2cfb90e..b33a5de 100644
--- a/tests/functional/tests/bundles/overlays/xenial.yaml.j2
+++ b/tests/functional/tests/bundles/overlays/xenial.yaml.j2
@@ -1 +1,4 @@
 series: xenial
+applications:
+  rabbitmq-server:
+    channel: 3.6/edge