tools/xl: add vlan keyword to vif option

Update parse_nic_config() to support a new `vlan' keyword. This
keyword specifies the VLAN configuration to assign to the VIF when
attaching it to the bridge port, on operating systems that support
the capability (e.g. Linux). The vlan keyword will allow one or
more VLANs to be configured on the VIF when adding it to the bridge
port. This will be done by the vif-bridge script and functions.

Signed-off-by: Leigh Brown <leigh@solinno.co.uk>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>

tools/xl/xl_parse.c

@@ -565,6 +565,8 @@ int parse_nic_config(libxl_device_nic *nic, XLU_Config **config, char *token)
         nic->devid = parse_ulong(oparg);
     } else if (MATCH_OPTION("mtu", token, oparg)) {
         nic->mtu = parse_ulong(oparg);
+    } else if (MATCH_OPTION("vlan", token, oparg)) {
+        replace_string(&nic->vlan, oparg);
     } else if (!strcmp("trusted", token)) {
         libxl_defbool_set(&nic->trusted, true);
     } else if (!strcmp("untrusted", token)) {