paramiko 2.0.0 pickling error with RSA private key object (regression)

Summary:
Pickling a RSAKey has been working fine in both paramiko 1.16.0 and 1.17.0. It no longer works in 2.0.0. Specifically, the code in question was picking the return of RSAKey.from_private_key.

Error:
Can't pickle <type '_cffi_backend.CDataGCP'>: it's not found as _cffi_backend.CDataGCP

Environment:
Python 2.7.6
Reproduced on OSX 1and Ubuntu.

Detailed Stack:
File "/usr/local/lib/python2.7/dist-packages/dill/dill.py", line 243, in dumps
dump(obj, file, protocol, byref, fmode, recurse)#, strictio)
File "/usr/local/lib/python2.7/dist-packages/dill/dill.py", line 236, in dump
pik.dump(obj)
File "/usr/lib/python2.7/pickle.py", line 224, in dump
self.save(obj)
File "/usr/lib/python2.7/pickle.py", line 286, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/local/lib/python2.7/dist-packages/dill/dill.py", line 835, in save_module_dict
StockPickler.save_dict(pickler, obj)
File "/usr/lib/python2.7/pickle.py", line 649, in save_dict
self._batch_setitems(obj.iteritems())
File "/usr/lib/python2.7/pickle.py", line 681, in _batch_setitems
save(v)
File "/usr/lib/python2.7/pickle.py", line 286, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/local/lib/python2.7/dist-packages/dill/dill.py", line 835, in save_module_dict
StockPickler.save_dict(pickler, obj)
File "/usr/lib/python2.7/pickle.py", line 649, in save_dict
self._batch_setitems(obj.iteritems())
File "/usr/lib/python2.7/pickle.py", line 681, in _batch_setitems
save(v)
File "/usr/lib/python2.7/pickle.py", line 331, in save
self.save_reduce(obj=obj, *rv)
File "/usr/lib/python2.7/pickle.py", line 419, in save_reduce
save(state)
File "/usr/lib/python2.7/pickle.py", line 286, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/local/lib/python2.7/dist-packages/dill/dill.py", line 835, in save_module_dict
StockPickler.save_dict(pickler, obj)
File "/usr/lib/python2.7/pickle.py", line 649, in save_dict
self._batch_setitems(obj.iteritems())
File "/usr/lib/python2.7/pickle.py", line 686, in _batch_setitems
save(v)
File "/usr/lib/python2.7/pickle.py", line 331, in save
self.save_reduce(obj=obj, *rv)
File "/usr/lib/python2.7/pickle.py", line 419, in save_reduce
save(state)
File "/usr/lib/python2.7/pickle.py", line 286, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/local/lib/python2.7/dist-packages/dill/dill.py", line 835, in save_module_dict
StockPickler.save_dict(pickler, obj)
File "/usr/lib/python2.7/pickle.py", line 649, in save_dict
self._batch_setitems(obj.iteritems())
File "/usr/lib/python2.7/pickle.py", line 681, in _batch_setitems
save(v)
File "/usr/lib/python2.7/pickle.py", line 331, in save
self.save_reduce(obj=obj, *rv)
File "/usr/lib/python2.7/pickle.py", line 396, in save_reduce
save(cls)
File "/usr/lib/python2.7/pickle.py", line 286, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/local/lib/python2.7/dist-packages/dill/dill.py", line 1231, in save_type
StockPickler.save_global(pickler, obj)
File "/usr/lib/python2.7/pickle.py", line 748, in save_global
(obj, module, name))
StatementError: (pickle.PicklingError) Can't pickle <type '_cffi_backend.CDataGCP'>: it's not found as _cffi_backend.CDataGCP

No source file or test is named. Start by reproducing the failure with Python 2.7, dill, and RSAKey.from_private_key, then trace how RSAKey state reaches the pickle operation. Done means RSAKey objects can be pickled without the reported _cffi_backend.CDataGCP error and the regression is covered by a repeatable check.