images: tty -- Reserve entries for multiple devpts support

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

images/tty.proto

@@ -39,6 +39,8 @@ enum TtyType {
 message tty_data_entry {
 	required uint32			tty_id		= 1;
 	required bytes			data		= 2;
+
+	// optional sint32		mnt_id		= 3 [default = 0];
 }
 
 message tty_info_entry {
@@ -73,6 +75,8 @@ message tty_info_entry {
 
 	optional uint32			uid		= 14;
 	optional uint32			gid		= 15;
+
+	// optional sint32		mnt_id		= 16 [default = 0];
 };
 
 message tty_file_entry {
@@ -81,5 +85,6 @@ message tty_file_entry {
 
 	required uint32			flags		= 3 [(criu).hex = true];
 	required fown_entry		fown		= 4;
+	// optional sint32		mnt_id		= 5 [default = 0];
 	optional uint32			regf_id		= 6;
 }