py34: fix exception conversion for logging
py34: fix exception conversion for logging

Change-Id: I4b31e9c397afa4704a482339bad67ecbc6afb1ff

openstack/ec2-api,hayderimran7/ec2-api,openstack/ec2-api,stackforge/ec2-api,hayderimran7/ec2-api,stackforge/ec2-api