exclude junit when testing zookeeper

it's a different version when we experiment with other version bumps, but isn't needed;
prevents dependency violations during builds in some cases
diff --git a/software/messaging/pom.xml b/software/messaging/pom.xml
index 8de19f1..bab0942 100644
--- a/software/messaging/pom.xml
+++ b/software/messaging/pom.xml
@@ -272,6 +272,10 @@
                     <groupId>log4j</groupId>
                     <artifactId>log4j</artifactId>
                 </exclusion>
+                <exclusion>
+                    <groupId>junit</groupId>
+                    <artifactId>junit</artifactId>
+                </exclusion>
             </exclusions>
         </dependency>
         <dependency>