This commit is to fix the issue for the following scenario:
1, user success migrate harbor to v1.9.0 from a previous version
2, add a project, push images into the project.
3, delete images and then to delete the project.
4, re-launch harbor.

After that, it still execute the quota migration as the condition doesn't consider the deleted projects usage.
And in this case, the harbor core crashes with a duplicate sql err, and unable to launch.

[Workaroud]
Clean table of project_blob with: TRUNCATE TABLE project_blob, and re-launch harbor, wait for quota sync success.

Signed-off-by: wang yan <wangyan@vmware.com>