fail to extract db and table name from dump filename

[csuzhangxc]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do? If possible, provide a recipe for reproducing the error.

   dump & load data with DM

2. What did you expect to see?

   no error happens

3. What did you see instead?

   [loader.go:957] [\"invalid db table sql file\"] [task=task_pessimistic] [unit=load] [file=db_pessimistic.sqlgaruh.0.sql] [error=\"db_pessimistic.sqlgaruh.0.sql doesn't have correct . seperator\"]

4. Versions of the cluster

   • DM version (run dmctl -V or dm-worker -V or dm-master -V):

     v2.0.0