test/emacs: reduce use of smtp-dummy, notmuch-hello

[David Bremner]

In addition to the timestamp related failures in the test suite,
there were some intermittent problems [1] that turned out to be failure of
the emacs_deliver_message function.  In this series we try to make
mail delivery from emacs more robust (mainly replace actual delivery
with fcc)

[1]: https://buildd.debian.org/fetch.cgi?pkg=notmuch&arch=i386&ver=0.17%7Erc3-1&stamp=1386412394&file=log

As I write this, the crypto tests have run successfully for 9155
times. Of course that doesn't really prove anything, but it is twice
as many as the previously longest interval before failure.