title: tomcat7-maven-plugin extraDependency seems not being loaded
body: <p>I've been using tomcat7-maven-plugin. I want to run my webapp which connects to the PostgreSQL database by using the embedded tomcat. This is the related part of my POM file:
  </p>
  
  <pre><code>&lt;plugin&gt;
      &lt;groupId&gt;org.apache.tomcat.maven&lt;/groupId&gt;
      &lt;artifactId&gt;tomcat7-maven-plugin&lt;/artifactId&gt;
      &lt;version&gt;2.0-SNAPSHOT&lt;/version&gt;
      &lt;executions&gt;
          &lt;execution&gt;
              &lt;id&gt;tomcat-run&lt;/id&gt;
              &lt;goals&gt;
                  &lt;goal&gt;exec-war-only&lt;/goal&gt;
              &lt;/goals&gt;
              &lt;phase&gt;package&lt;/phase&gt;
              &lt;configuration&gt;
                  &lt;path&gt;/&lt;/path&gt;
                  &lt;attachArtifactClassifierType&gt;war&lt;/attachArtifactClassifierType&gt;
                  &lt;enableNaming&gt;true&lt;/enableNaming&gt;
                  &lt;extraDependencies&gt;
                      &lt;extraDependency&gt;
                          &lt;groupId&gt;postgresql&lt;/groupId&gt;
                          &lt;artifactId&gt;postgresql&lt;/artifactId&gt;
                          &lt;version&gt;8.4-701.jdbc4&lt;/version&gt;
                      &lt;/extraDependency&gt;
                  &lt;/extraDependencies&gt;
              &lt;/configuration&gt;
         &lt;/execution&gt;
     &lt;/executions&gt;
  </code></pre>
  
  <p></p>
  
  <p>Executing tomcat7:run fails with</p>
  
  <pre><code>Caused by: java.lang.ClassNotFoundException: org.postgresql.Driver
  at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:50)
  at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:244)
  at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:230)
  at java.lang.Class.forName0(Native Method)
  at java.lang.Class.forName(Class.java:247)
  at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:236)
  ... 29 more
  </code></pre>
  
  <p>The dependency itself is correct (http://repo1.maven.org/maven2/postgresql/postgresql/8.4-701.jdbc4/).</p>
  
  <p>I use Maven 3.</p>