Update the default_log_levels defaults

The default for default_log_levels didn't set the log levels
for some packages that Keystone uses (for example, dogpile). This
caused the server to output a lot of extra logs when debug=True
is used.

You can get the debug output for dogpile and routes by setting
default_log_levels explicitly in your keystone.conf file.

Change-Id: Ib797fa7b98f0e501047b72b094d07ad204385cc6
Related-bug: #1245629
Closes-Bug: #1269987
Merge "Update the default_log_levels defaults"