Correct sample config default log levels

The documentation of the default_log_levels default value in the
sample keystone.conf file was out of date. The default value has
been updated to the current value in keystone.openstack.common.log.

Change-Id: I3edf2d5375413250de41f8cebb98a826dc5df8ce
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
Implement list limiting support in driver backends

Provides an optional limit to the number of rows that will be
returned by a backend from a list_{entity} call.  The limit is specified
in the configuration file, and allows for an overall general limit as
well as an individual limit for a given driver.  By default, there is
no limit.

Limitations:
    - The list limit is not yet handled by LDAP, rather this remains
      implemented in the final wrap collection - a subsequent patch
      will provide the support in the LDAP drivers

Implements bp list-limiting

Change-Id: I7ca76a8da4260242e578c44103b26257f7e2a5d5
Limit calls to memcache backend as user token index increases in size

This eliminates the need to do a get on each token in the user's index
on token issuance. This change will change the maximum number of tokens
that can be outstanding for a given user. This change is two-fold, first
instead of using JSON to store the token IDs, the python list structure
is being stored in memcached; second the expiry for the token is also
stored in the list. The net result is that fewer tokens can be stored
in the user's token index list due to an increase in data being stored
per token in the index page.

The new logic will attempt to upgrade the old json-style lists to
the new format of [(token_id, expiry), ...] stored as a native
python object in the memcache backend. This conversion will keep
any outstanding tokens in the list from (<time_of_conversion> +
<configured expiration of tokens>). This is done to ensure that
tokens can still be invalidated by operations that invalidate
tokens based upon user/project/trust/etc changes without causing
potential lockups in keystone trying to retrieve all of the
actual token expiration times from memcache.

Closes-bug: #1251123
Change-Id: Ida39b4699ed6c568609a5121573fc3be5c4ab2f4
Merge "Correct sample config default log levels"
Merge "Update the default_log_levels defaults"
Merge "Implement list limiting support in driver backends"
Merge "Limit calls to memcache backend as user token index increases in size"