Windows: Fix go test in execdriver\lxc

Signed-off-by: John Howard <jhoward@microsoft.com>

daemon/execdriver/lxc/lxc_init_unsupported.go

@@ -2,6 +2,10 @@
 
 package lxc
 
+// InitArgs contains args provided to the init function for a driver
+type InitArgs struct {
+}
+
 func finalizeNamespace(args *InitArgs) error {
 	panic("Not supported on this platform")
 }