add maven settings file for jenkins user

This commit is a workaround for jenkins issue
https://issues.jenkins-ci.org/browse/JENKINS-13637

This issue was uncovered when attempting to build the jenkins
gearman-plugin using maven3.

Change-Id: I5fdb20756f4ebca45b8e6eb2f114d561e1cca944
Reviewed-on: https://review.openstack.org/23022
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: James E. Blair <corvus@inaugust.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins