Add a per-test log

This patch adds a new per-test logging feature to Patrole
To accomplish this, it adds two new config variables

The logging now prints a log message containing the results of each RBAC
test to a separate log file, as well as to the normal
tempest.log file. This message is of the form:
[Service] <nova, neutron, etc>
[Test] <name of the test's method>
followed by either the result of the test as Allowed/Denied/Error, or
the expected result (from oslopolicy) and then the actual result

There are two new config variables that control this, added in a new
config group called patrole_log:
enable_reporting - defaults to True, which enables this new logging
functionality
report_log_name - defaults to patrole.log, controls the name of the log
the output is written to.
report_log_path - Defaults to the local directory, path (relative or
absolute) where to store the log

Change-Id: Iff2176f1a7c7d10f78b96d748f1d70b222fd5072
8 files changed