libsql: Fix SyncContext::new() metadata reading

If we fail to read the metadata file, we must return an error. Resetting
the metadata leads to inconsistent state because you have no way to tell
what the database represents.

Author: penberg

libsql/src/sync.rs

@@ -171,14 +171,10 @@ impl SyncContext {
             initial_server_sync: false,
             remote_encryption,
         };
-
-        if let Err(e) = me.read_metadata().await {
-            tracing::error!(
-                "failed to read sync metadata file, resetting back to defaults: {}",
-                e
-            );
+        me.read_metadata().await?;
+        if me.durable_generation == 0 {
+            return Err(SyncError::InvalidLocalState("generation is 0".to_string()).into());
         }
-
         Ok(me)
     }