disallow invalid VLAN/VNI value during network creation (#1069)

* Disallow invalid VLAN/VNI value during network creation

Currently, netctl parse the pkgTag input as an integer directly.
Therefore when user put a garbage in pkgTag, the conversion will
default it to 0 instead.

This patchset is to cast the input to string and perform further
validation logic before we create network

Signed-off-by: Kahou Lei <[email protected]>

* Update the patchset to use IntFlag instead.

Author: kahou82

netctl/commands.go

@@ -216,9 +216,9 @@ var Commands = []cli.Command{
 						Usage: "Encap type (vlan or vxlan)",
 						Value: "vxlan",
 					},
-					cli.StringFlag{
+					cli.IntFlag{
 						Name:  "pkt-tag, p",
-						Usage: "Packet tag (Vlan/Vxlan ids)",
+						Usage: "Packet tag (Vlan ID/VNI)",
 					},
 					cli.StringFlag{
 						Name:  "subnet, s",