clean up the camel-cxf pom

git-svn-id: https://svn.apache.org/repos/asf/camel/trunk@1458239 13f79535-47bb-0310-9956-ffa450edef68
CAMEL-6171 camel-cxf - Should detect existing User-Agent header to avoid adding duplicate

git-svn-id: https://svn.apache.org/repos/asf/camel/trunk@1458241 13f79535-47bb-0310-9956-ffa450edef68