Remove redundent logic from below.

Author: ericholscher

readthedocs/projects/tasks.py

@@ -1331,12 +1331,6 @@ def _manage_imported_files(version, path, commit):
     # Safely delete from database
     delete_queryset.delete()
 
-    # Delete ImportedFiles from previous versions
-    (
-        ImportedFile.objects.filter(project=version.project,
-                                    version=version).exclude(commit=commit
-                                                             ).delete()
-    )
     changed_files = [
         resolve_path(
             version.project,