Code review comment for lp:~sinzui/launchpad/entitlement-2

This branch looks good, the only comments I have are concerning code
that hasn't actually changed, so take that into consideration:

Is it possible that the strings included in the body of the email might
be wider than is customary for email messages? If so, we can use the
textwrap.fill function to tame the long lines.

It's arguable as to whether this is an improvement or not, but it
occurred to me that _indent() could be implemented with this regex:

    re.sub('^', ' '*4, text, flags=re.M)

Using the string "Commercial" as the display-name portion of the from
address seems a little vague. Maybe something like "Launchpad
Commercial Services" (or a shorter variation) would be nicer.