Maven: Clean up pom.xml

Axis and wsdl2java stub generation stuff was apparently copied from
its-jira's pom.xml and was forgotten. Clean it up, as it is unused.

Also Gerrit-Module was defined twice.  Let's define it only once and
with the right name.

Change-Id: I1862dc47cb5e5d4cec3275656b2f2f85011ab10c