Clean up logging from glance_http.py

Currently the logging in the glance_http module is overly
verbose and doesn't add any extra useful information. This
commit condenses the logging and makes it analogous to the
logging in rest_client.py

Fixes bug 1089765

Change-Id: Ifa7038de27d979a60ff36b6e32b2cbe85541c231
1 file changed