In security-spi/parent/pom.xml:
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>

In security-spi/spi/pom.xml:
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
</dependency>

This dependency should be changed to:
<dependency>
<groupId>org.jboss.spec.javax.servlet</groupId>
<artifactId>jboss-servlet-api_3.0_spec</artifactId>
<version>1.0.0.Final</version>
</dependency>

because the Servlet API in AS 7 is 3.0