log: add logger.conf.example file

This example file can be safely renamed as logger.conf to enable
syslog logging

Change-Id: If49dd6002a046915b2eca330b7a539f4fa1f94fa
BUG: 928648
Signed-off-by: Bala.FA <barumuga@redhat.com>
Reviewed-on: http://review.gluster.org/5622
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>