title: Weird dependency convergence error
body: <p>Here's error I see in maven build command. The weird thing I found is that the version of zeppelin-interpreter is 0.8.0-20170724.234851-5, but not 0.8.0-SNAPSHOT. In the last commit I do specify guava version as 15.0, and I updated it to 18.0 in the new commit. But I don't understand why zeppelin-zengine still depends on the old version 0.8.0-20170724.234851-5 instead of 0.8.0-SNAPSHOT. Anyone can help on that ? Thanks</p>
  
  <pre><code>Dependency convergence error for com.google.guava:guava:15.0 paths to dependency are:
      +-org.apache.zeppelin:zeppelin-zengine:0.8.0-SNAPSHOT
        +-org.apache.zeppelin:zeppelin-interpreter:0.8.0-20170724.234851-5
          +-com.google.guava:guava:15.0
      and
      +-org.apache.zeppelin:zeppelin-zengine:0.8.0-SNAPSHOT
        +-com.google.guava:guava:18.0
  </code></pre>