Refuse files with unknown bits set (fixes #1276)

Godeps/Godeps.json

@@ -35,7 +35,7 @@
 		},
 		{
 			"ImportPath": "github.com/syncthing/protocol",
-			"Rev": "442e93d3fc7728d7560c8d039a4199a77879b9f6"
+			"Rev": "4395711d26c61e7e422a8c8da43dda164f1820f4"
 		},
 		{
 			"ImportPath": "github.com/syndtr/goleveldb/leveldb",

Godeps/_workspace/src/github.com/syncthing/protocol/protocol.go

@@ -43,6 +43,8 @@ const (
 	FlagSymlink                     = 1 << 16
 	FlagSymlinkMissingTarget        = 1 << 17
 
+	FlagsAll = (1 << iota) - 1
+
 	SymlinkTypeMask = FlagDirectory | FlagSymlinkMissingTarget
 )