cherry_picker hardcodes the name of the python/cpython.git repo

[markshannon]

cherry_picker needs an option to specify the git remote name for the CPython repo.
Currently it is hardcoded to "upstream" or "origin", and can't be used if a meaningful name like "python" is used
E.g.

~/repos/cpython$ git remote -v
python	git@github.com:python/cpython.git (fetch)
python	git@github.com:python/cpython.git (push)
mine	git@github.com:markshannon/cpython.git (fetch)
mine	git@github.com:markshannon/cpython.git (push)

[Mariatta]

Perhaps we can add yet another option to specify the upstream.
Right now it only recognizes either upstream or origin.

cherry-picker/cherry_picker/cherry_picker.py

Lines 137 to 146 in 39e8d6d

	def upstream(self):
	"""Get the remote name to use for upstream branches
	Uses "upstream" if it exists, "origin" otherwise
	"""
	cmd = ["git", "remote", "get-url", "upstream"]
	try:
	subprocess.check_output(cmd, stderr=subprocess.DEVNULL)
	except subprocess.CalledProcessError:
	return "origin"
	return "upstream"

PR is welcome.