"container" field of SiteDeployMojo not populated correctly -> NPE with servers containing configuration

In SiteDeployMojo, the field "container" is not populated correctly (version skew with @Requirement?). When configureWagon is subsequently called, IFF the site deploy server has an entry in settings.xml AND contains a "configuration" subelement, there will be a NullPointerException thrown (line 474) when container.lookup is called.
Simple repro:

settings.xml:
...
<server>
<id>bogus</id>
<username>bogus</username>
<password>bogus</password>
<configuration>
</configuration>
</server>
...

pom.xml:
...
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-site-plugin</artifactId>
<version>3.0-beta-3</version>
</plugin>
</plugins>
</build>
<distributionManagement>
<site>
<id>bogus</id>
<name>Bogus</name>
<url>sftp://bogus.bogus.org/bogus</url>
</site>
</distributionManagement>
...

While this should obviously not work, it should not NPE at line 474.