Do not process OSS Fuzz in delete-only mode (#2200)

I noticed this was not behaving as intended during manual dry-run
testing in Production.

docker/importer/importer.py

@@ -182,7 +182,7 @@ def _request_internal_analysis(self, bug):
   def run(self):
     """Run importer."""
     for source_repo in osv.SourceRepository.query():
-      if source_repo.name == 'oss-fuzz':
+      if not self._delete and source_repo.name == 'oss-fuzz':
         self.process_oss_fuzz(source_repo)
 
       self.validate_source_repo(source_repo)