.......... [ZBXNEXT-826] updated release version [2.5.0]; updated API version [2.5.0]

git-svn-id: svn://svn.zabbix.com/trunk@48963 f4e7fd02-d210-4e34-a1e0-d4093fb66cc2
.......... [ZBXNEXT-826] updated release version [2.4.1rc1]; updated API version [2.4.1]

git-svn-id: svn://svn.zabbix.com/trunk@48964 f4e7fd02-d210-4e34-a1e0-d4093fb66cc2
....I..... [ZBXNEXT-826] added empty database upgrade module for version 2.5.0

git-svn-id: svn://svn.zabbix.com/trunk@48965 f4e7fd02-d210-4e34-a1e0-d4093fb66cc2