This was not the correct way to fix the issue.

* Calling "vim-patch.sh -p" on a checked-out branch already created with
  "-p" will re-use the branch and append commits.

* Fetch upstream/master before checking out branch on first call of "-p".

* Reverted creation of commit in submit step ("-s") to previous behavior:
  Create an empty commit with correct commit message when "-p" is called.

* Submitting a pull request with "-s" will create a correct pull request
  message even if multiple patches have been ported in one single branch
  with "-p".

When calling "vim-patch.sh -s" on a checked-out branch created with
"vim-patch.sh -p", create commit from staged changes, push to origin,
create pull request (using hub), and clean up patch files.

 * Support pull requests with multiple commits.
 * Offer to clean up files after review.
 * Always use full commit hash in assign_commit_details().

Problem:    For some options two consecutive commas are OK. (Nikolay Pavlov)
Solution:   Add the P_ONECOMMA flag.

https://github.com/vim/vim/commit/0e7c4b99c608d22fd1b8526e700420b248319b1f

This will avoid confusion if additional `it()` blocks are added.
(`setup()` only runs once per `describe()` block, whereas `before_each()`
runs before each `it()`).