Avoid using Jenkins CI Maven Repo for snapshot artifacts

Snapshot artifacts are typically provided by the
GerritForge CI and thus do not have to be searched
in Jenkins maven repo.

Change-Id: I3472e4fb4a0c414ff00cf261e7be36815450e9ac

pom.xml

diff --git a/pom.xml b/pom.xml
index 3710b03..de0516d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -249,6 +249,12 @@
   </build>
   <repositories>
     <repository>
+      <releases>
+        <enabled>true</enabled>
+      </releases>
+      <snapshots>
+        <enabled>false</enabled>
+      </snapshots>
       <id>repo.jenkins-ci.org</id>
       <url>http://repo.jenkins-ci.org/public/</url>
     </repository>