Cleanup: re-run autopep8 with E401 enabled

Put imports on their own line which was almost always the case already.

doc/blender_file_format/BlendFileDnaExporter_25.py

@@ -378,7 +378,8 @@ def usage():
 
 def main():
 
-    import os, os.path
+    import os
+    import os.path
 
     try:
         bpy = __import__('bpy')