Improvements:
[system] add more information to supportsave about zproxy process
[cluster] protect backup from master updates when upgrading the system
Bugfixes:
[farms] fix the backend routing rules for l4xnat farms
[stats] fix an error in HTTP backend stats
[farms] enable a minimum log level for HTTP farms
[system] fix an error dumping sessions information in supportsave
[rbac] fix an error retrieving the list of expected parameters in adding RBAC user ZAPI request