py34: fix exception formatting to user-friendly message
py34: fix exception formatting to user-friendly message

ex.args in python3 is a tuple of all arguments that was passed to exception init

Change-Id: I32c16965e3f0a62371c3a99811d34f697c5a3246

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