enable dnsplugin for network create

when users create a new network and the dnsname plugin can be found by
podman, we will enable container name resolution on the new network.
there is an option to opt *out* as well.

tests cannot be added until we solve the packaging portion of the
dnsname plugin.

Signed-off-by: baude <bbaude@redhat.com>

cmd/podman/cliconfig/config.go

@@ -267,6 +267,7 @@ type MountValues struct {
 type NetworkCreateValues struct {
 	PodmanCommand
 	Driver     string
+	DisableDNS bool
 	Gateway    net.IP
 	Internal   bool
 	IPamDriver string

cmd/podman/network_create.go

@@ -46,7 +46,7 @@ func init() {
 	// TODO enable when IPv6 is working
 	//flags.BoolVar(&networkCreateCommand.IPV6, "IPv6", false, "enable IPv6 networking")
 	flags.IPNetVar(&networkCreateCommand.Network, "subnet", net.IPNet{}, "subnet in CIDR format")
-
+	flags.BoolVar(&networkCreateCommand.DisableDNS, "disable-dns", false, "disable dns plugin")
 }
 
 func networkcreateCmd(c *cliconfig.NetworkCreateValues) error {