Add ::1 where we see 127.0.0.1, for better ipv6 support

Fixes #5764

lib/ansible/inventory/__init__.py

@@ -372,7 +372,7 @@ class Inventory(object):
                     for host in matching_hosts:
                         __append_host_to_results(host)
 
-        if pattern in ["localhost", "127.0.0.1"] and len(results) == 0:
+        if pattern in ["localhost", "127.0.0.1", "::1"] and len(results) == 0:
             new_host = self._create_implicit_localhost(pattern)
             results.append(new_host)
         return results
@@ -408,9 +408,9 @@ class Inventory(object):
         return self._hosts_cache[hostname]
 
     def _get_host(self, hostname):
-        if hostname in ['localhost','127.0.0.1']:
+        if hostname in ['localhost', '127.0.0.1', '::1']:
             for host in self.get_group('all').get_hosts():
-                if host.name in ['localhost', '127.0.0.1']:
+                if host.name in ['localhost', '127.0.0.1', '::1']:
                     return host
             return self._create_implicit_localhost(hostname)
         else:
@@ -512,7 +512,7 @@ class Inventory(object):
         """ return a list of hostnames for a pattern """
 
         result = [ h for h in self.get_hosts(pattern) ]
-        if len(result) == 0 and pattern in ["localhost", "127.0.0.1"]:
+        if len(result) == 0 and pattern in ["localhost", "127.0.0.1", "::1"]:
             result = [pattern]
         return result