title: Why this unexpected composer version result?
body: <p>I have the following two packages </p>
  
  <p>Package : <code>"my/package"</code><br>
  Releases <code>0.8.9, 0.8.8, 0.8.7, 0.8.6, 0.8.5, 0.8.4, 0.8.3, 0.8.2, 0.8.1, 0.8.0, 0.7.4, ...</code></p>
  
  <p>Package : <code>"my/package2"</code><br>
  Releases: <code>0.1.1, 0.1.0</code></p>
  
  <p>My default composer.json config with strange behavior installs:</p>
  
  <pre><code>{
    "minimum-stability" : "stable",
    "require" :           {
      "my/package" :    "*",
      "my/package2" :   "*"
    }
  }
  </code></pre>
  
  <p>Result:</p>
  
  <ul>
  <li><code>"my/package"@0.8.0</code></li>
  <li><code>"my/package2"@0.1.1</code></li>
  </ul>
  
  <p>If I change the config to the following:</p>
  
  <pre><code>{
    "prefer-stable": true,
    "minimum-stability" : "dev",
    "require" :           {
      "my/package" :    "*",
      "my/package2" :   "*"
    }
  }
  </code></pre>
  
  <p>Result:</p>
  
  <ul>
  <li><code>"my/package"@0.8.9</code></li>
  <li><code>"my/package2"@0.1.1</code></li>
  </ul>
  
  <p>why installs my default config <code>"my/package"@0.8.0</code> and not <code>@0.8.9</code>?</p>