remove check_db_setup

This won't be feasible if the sqlite database file name changes or if
support for out-of-process databases is added.

src/database.rs

@@ -233,61 +233,6 @@ pub(crate) struct KeyValueDatabase {
 }
 
 impl KeyValueDatabase {
-    fn check_db_setup(config: &Config) -> Result<()> {
-        let path = Path::new(&config.database.path);
-
-        let sqlite_exists = path
-            .join(format!(
-                "{}.db",
-                if config.conduit_compat {
-                    "conduit"
-                } else {
-                    "grapevine"
-                }
-            ))
-            .exists();
-        let rocksdb_exists = path.join("IDENTITY").exists();
-
-        let mut count = 0;
-
-        if sqlite_exists {
-            count += 1;
-        }
-
-        if rocksdb_exists {
-            count += 1;
-        }
-
-        if count > 1 {
-            warn!("Multiple databases at database_path detected");
-            return Ok(());
-        }
-
-        let (backend_is_rocksdb, backend_is_sqlite): (bool, bool) =
-            match config.database.backend {
-                #[cfg(feature = "rocksdb")]
-                DatabaseBackend::Rocksdb => (true, false),
-                #[cfg(feature = "sqlite")]
-                DatabaseBackend::Sqlite => (false, true),
-            };
-
-        if sqlite_exists && !backend_is_sqlite {
-            return Err(Error::bad_config(
-                "Found sqlite at database_path, but is not specified in \
-                 config.",
-            ));
-        }
-
-        if rocksdb_exists && !backend_is_rocksdb {
-            return Err(Error::bad_config(
-                "Found rocksdb at database_path, but is not specified in \
-                 config.",
-            ));
-        }
-
-        Ok(())
-    }
-
     pub(crate) fn load_or_create_engine(
         config: &Config,
     ) -> Result<Arc<dyn KeyValueDatabaseEngine>> {
@@ -296,8 +241,6 @@ impl KeyValueDatabase {
             "Compiled without support for any databases",
         ));
 
-        Self::check_db_setup(config)?;
-
         if !Path::new(&config.database.path).exists() {
             fs::create_dir_all(&config.database.path).map_err(|_| {
                 Error::BadConfig(