lib/db: Remove Badger experiment (#7413)

lib/locations/locations.go

@@ -47,7 +47,6 @@ const (
 	UserHomeBaseDir BaseDirEnum = "userHome"
 
 	LevelDBDir = "index-v0.14.0.db"
-	BadgerDir  = "indexdb.badger"
 )
 
 // Platform dependent directories
@@ -160,16 +159,9 @@ func defaultDataDir(userHome, config string) string {
 
 	default:
 		// If a database exists at the "normal" location, use that anyway.
-		// We look for both LevelDB and Badger variants here regardless of
-		// what we're currently configured to use, because we might be
-		// starting up in Badger mode with only a LevelDB database present
-		// (will be converted), or vice versa.
 		if _, err := os.Lstat(filepath.Join(config, LevelDBDir)); err == nil {
 			return config
 		}
-		if _, err := os.Lstat(filepath.Join(config, BadgerDir)); err == nil {
-			return config
-		}
 		// Always use this env var, as it's explicitly set by the user
 		if xdgHome := os.Getenv("XDG_DATA_HOME"); xdgHome != "" {
 			return filepath.Join(xdgHome, "syncthing")