[ArmZabbixAPI] Remove a needless property in "apiinfo.version" method
[testArmZabbixAPI] Replace a nonexistent API version number with an actual one

The version number of Zabbix 2.0.4 (or later) is same with the
version of Zabbix. On the other hand older one isn't match with
Zabbix's version. For example the API version of Zabbix 2.0.3 is
1.4.