Downgrade axiom due to install issue in Karaf

Version 1.2.14 of axiom causes the following error when installing in Karaf:
"Error executing command: Manifest not present in the first entry of the zip mvn:org.apache.ws.commons.axiom/axiom-impl/1.2.14"

Same issue reported against camel (https://issues.apache.org/jira/browse/CAMEL-6059), so suggesting the same approach - downgrade to 1.2.12.