Introduce IPv6 constants

Signed-off-by: Manuel Franceschini <livewire@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

lib/constants.py

@@ -436,6 +436,8 @@ DEFAULT_BRIDGE = "xen-br0"
 SYNC_SPEED = 60 * 1024
 IP4_ADDRESS_LOCALHOST = "127.0.0.1"
 IP4_ADDRESS_ANY = "0.0.0.0"
+IP6_ADDRESS_LOCALHOST = "::1"
+IP6_ADDRESS_ANY = "::"
 TCP_PING_TIMEOUT = 10
 GANETI_RUNAS = "root"
 DEFAULT_VG = "xenvg"
@@ -635,7 +637,7 @@ HTS_REQ_PORT = frozenset([HT_XEN_HVM, HT_KVM])
 
 VNC_BASE_PORT = 5900
 VNC_PASSWORD_FILE = CONF_DIR + "/vnc-cluster-password"
-VNC_DEFAULT_BIND_ADDRESS = IP4_ADDRESS_ANY 
+VNC_DEFAULT_BIND_ADDRESS = IP4_ADDRESS_ANY
 
 # NIC types
 HT_NIC_RTL8139 = "rtl8139"