util_win32.py: fix user_rcpath Fixes issue504.

Combined the two os_rcpath methods into a single one near rcpath in mercurial/util.py The os_rcpath method delegates to system_rcpath and user_rcpath from the different platform implementations.

merge with crew-stable

hgweb: catch util.Abort raised by addchangegroup Right now, if a pretxnchangegroup hook fails, we send some HTML error message to the client and the transaction is not rolled back (issue499). Catching util.Abort allows us to send a decent message to the client and for some reason makes the rollback complete. This patch is not perfect since it doesn't fix the reason why the transaction wasn't rolled back (maybe some circular references?). Also, the transaction is aborted only after we've sent the response back to the client and the "transaction aborted" message ends up in the logs of the web server.

notify: don't try to fix addresses if notify.domain is not set

mail.py: don't try to use TLS if python doesn't have SSL support This should hide the traceback from issue501.