[mimp] default identity's address getting set incorrectly

[Liam Hoekenga]

I'm using the HEAD version of MIMP.  When I try to compose email in MIMP, my
outgoing address gets set to..

    liamr@

Now.. if I try this in my desktop browser, and log into horde, and then go to
the MIMP url, it says the right thing.. (eg "liamr at example.com").  But if I
haven't fully logged into horde, it doesn't seem to pick up the default domain.

Any ideas?

Liam