..F.I..... [ZBX-7849] fixed not being able to save actions with a "Maintenance status" condition after upgrading from 2.0

Before the fix:
- In 2.2 it was possible to create a "Maintenance status" action condition with value "0". In ZBX-6808 maintenance validation has been changed to only allow empty values for this condition type and trigger an error if a different value had been given. Thus, after upgrading from 2.0 some of the "Maintenance status" action conditions could still have "0" values that caused an error when trying to save the action.
 
 After the fix:
 - A patch has been added to change values for these action conditions from "0" to "".

git-svn-id: svn://svn.zabbix.com/trunk@43321 f4e7fd02-d210-4e34-a1e0-d4093fb66cc2
..F....... [ZBX-7749] fixed incorrect login attempt count

git-svn-id: svn://svn.zabbix.com/trunk@43330 f4e7fd02-d210-4e34-a1e0-d4093fb66cc2
...G...PS. [ZBX-4998] fixed inconsistency of logging on Linux and Windows agents, and fixed information level logging at debug level 0

git-svn-id: svn://svn.zabbix.com/trunk@43337 f4e7fd02-d210-4e34-a1e0-d4093fb66cc2
........S. [ZBX-5778] removed counting items in queue if host is in maintenance with no data collection

git-svn-id: svn://svn.zabbix.com/trunk@43343 f4e7fd02-d210-4e34-a1e0-d4093fb66cc2
..F.....S. [ZBX-7872] removed discovery item prototype from calculation of required performace (NVPS)

git-svn-id: svn://svn.zabbix.com/trunk@43350 f4e7fd02-d210-4e34-a1e0-d4093fb66cc2