title: Meteor version solver: why does "meteor update" downgrade packages?
body: <p>I have this in a package:</p>
  
  <pre><code>  api.use([
      'kestanous:herald@1.1.3',
      'kestanous:herald-email',
    ]);
  </code></pre>
  
  <p>As expected, Meteor uses version 1.1.3 of the Herald package. </p>
  
  <p>If I <em>remove</em> the <code>@1.1.3</code> version, the package's <code>versions.json</code> doesn't change. </p>
  
  <p>But now if I run <code>meteor update kestanous:herald</code>, here's what I get:</p>
  
  <pre><code>$ meteor update kestanous:herald
  
  Changes to your project's package version selections from updating package versions:
  
  kestanous:herald  downgraded from 1.1.3 to 1.0.1
  </code></pre>
  
  <p>It doesn't make sense to me that upgrading a package would actually <em>downgrade</em> it. Especially since <code>kestanous:herald</code> is used nowhere else in the app. Even stranger, there are still no changes to the package's <code>versions.json</code> file despite the message. </p>
  
  <p>So it seems either I don't understand how package versioning works, or else something is not working correctly?</p>