Merge autopkgtest-cloud:pin-rabbitmq-charm into autopkgtest-cloud:master

[Brian Murray]

We ran into a bug (charm stuck in waiting) when upgrading to revision 177 of the rabbitmq-server charm and managed to work around it by downgrading to revision 176. Let's commit that change to the service-bundle until the charm is sorted.

[Tim Andersson (andersson123)]

review: Approve

diff --git a/mojo/service-bundle b/mojo/service-bundle
index 6a60e35..dfb3c94 100644
--- a/mojo/service-bundle
+++ b/mojo/service-bundle
@@ -251,6 +251,7 @@ applications:
 {%- endif %}
     rabbitmq-server:
         charm: cs:rabbitmq-server
+        revision: 176
         constraints: mem=8G
         expose: true
         num_units: 1