The current object change detection actually just hashed the method
argspecs of the remotable decorators instead of the wrapped methods
themselves. This patch fixes that by stashing a pointer to the
original function, which is used for the hash and will be useful
for other inspection-related tasks as well.
This also adds a utility to help when regenerating the hashes,
similar to what we do for API samples. Running the unit tests like
this will give you an object_hashes.txt output file:
GENERATE_HASHES=y tox TestObjectVersions
Change-Id: Icfe4d6c08f42296c756d1f9ab7c88b52e3209d84