python lib: rename rpc.py to rpc_pb2.py

Unfortunately, newer versions of protobuf check that the file suffix ends
in _pb2.py:

sudo ./zdtm.py run -t zdtm/static/apparmor_stacking
Traceback (most recent call last):
  File "./zdtm.py", line 23, in <module>
    import criu as crpc
  File "/home/ubuntu/criu/test/criu.py", line 12, in <module>
    import rpc
  File "/home/ubuntu/criu/test/rpc.py", line 36, in <module>
    type=None),
  File "/usr/lib/python2.7/dist-packages/google/protobuf/descriptor.py", line 652, in __new__
    _message.Message._CheckCalledFromGeneratedFile()
TypeError: Descriptors should not be created directly, but only retrieved from their parent.

v2: fix up the clean target, and remove some comments that were about the
    old rename
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
CC: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

lib/py/.gitignore

 *_pb2.py
 *.pyc
-rpc.py

lib/py/Makefile

-all: images rpc.py
+all: images rpc_pb2.py
 
 .PHONY: all images clean
 
 images:
 	$(Q) $(MAKE) -C images all
 
-# rpc_pb2.py doesn't depend on any other file, so
-# it is safe to rename it, dropping ugly _pb2 suffix.
-rpc.py:
-	$(Q) protoc -I=$(SRC_DIR)/images/ --python_out=./ $(SRC_DIR)/images/$(@:.py=.proto)
-	$(Q) mv $(@:.py=_pb2.py) $@
+rpc_pb2.py:
+	$(Q) protoc -I=$(SRC_DIR)/images/ --python_out=./ $(SRC_DIR)/images/$(@:_pb2.py=.proto)
 
 clean:
 	$(Q) $(MAKE) -C images clean
-	$(Q) $(RM) rpc.py *.pyc
+	$(Q) $(RM) rpc_pb2.py *.pyc

lib/py/__init__.py

-import rpc
+import rpc_pb2 as rpc
 import images
 from criu import *

lib/py/criu.py

@@ -9,7 +9,7 @@ import signal
 import sys
 import struct
 
-import rpc
+import rpc_pb2 as rpc
 
 class _criu_comm:
 	"""

test/rpc.py

-../lib/py/rpc.py
\ No newline at end of file

test/rpc_pb2.py

+../lib/py/rpc_pb2.py
\ No newline at end of file