Add liwei to contributor list
Add liwei to contributor list

Change-Id: Ie41b3e43d8030fb0f3ea7f6f2b94047cbe5a332f

openstack/stackalytics,openstack/stackalytics,Mirantis/stackalytics,Mirantis/stackalytics,0xf2/stackalytics,0xf2/stackalytics,stackforge/stackalytics,0xf2/stackalytics,stackforge/stackalytics,openstack/stackalytics,Mirantis/stackalytics,openstack/stackalytics,stackforge/stackalytics,0xf2/stackalytics