Neutron unhardcode logger log level

This patch unhardcodes log level in logging.conf template
The log level might be configured per logger by using the
following pillar structure:
 neutron:
   server:
     logging:
       loggers:
         <logger_name>:
            level: WARNING

Change-Id: I19ac0540f4a1a55f77f767b610b569df9fea16f7
Related-Prod: PROD-19782
2 files changed