Update dynamic inventory zabbix.py (#19862)

Added _meta to improve the speed when using this dynamic inventory file

contrib/inventory/zabbix.py

@@ -24,10 +24,12 @@ Zabbix Server external inventory script.
 ========================================
 
 Returns hosts and hostgroups from Zabbix Server.
+If you want to run with --limit against a host group with space in the 
+name, use asterisk. For example --limit="Linux*servers".
 
 Configuration is read from `zabbix.ini`.
 
-Tested with Zabbix Server 2.0.6.
+Tested with Zabbix Server 2.0.6 and 3.2.3.
 """
 
 from __future__ import print_function
@@ -102,6 +104,9 @@ class ZabbixInventory(object):
 
                 data[groupname]['hosts'].append(hostname)
 
+	# Prevents Ansible from calling this script for each server with --host
+        data['_meta'] = { 'hostvars': self.meta }
+
         return data
 
     def __init__(self):
@@ -110,6 +115,7 @@ class ZabbixInventory(object):
         self.zabbix_server   = None
         self.zabbix_username = None
         self.zabbix_password = None
+        self.meta            = {}
 
         self.read_settings()
         self.read_cli()