mail: split out the SMTP login to allow the keyring extension to wrap it
The keyring extension only needs to tweak this tiny section of the larger
function. But without any place to intercept the username/password fetching, it
copy/pasted the entire function, and has grown a bunch of compatibility hacks to
support older versions of Mercurial as well.
Differential Revision: https://phab.mercurial-scm.org/D10471
== New Features ==
* The amend extension supports the `--currentuser` argument.
* The amend extension supports the `--close-branch` argument.
* The amend extension supports the `--secret` argument.
* The uncommit extension supports the `rewrite.update-timestamp` config option.
== New Experimental Features ==
== Bug Fixes ==
== Backwards Compatibility Changes ==
* A shell that supports `$(command)`` syntax for command substitution is now
required for running the test suite. The test runner normally uses
`sh`, so if that is a shell that doesn't support `$(command)` syntax,
you can override it by setting `$HGTEST_SHELL` or by passing it to
`run-tests.py --shell <shell>`.
* The (experimental) narrow extension's wire protocol changed. If
you're using it, you'll need to make sure to upgrade server and
client at the same time.
== Internal API Changes ==