ports/155556: [PATCH] mail/davmail: Deobfuscate rc script and add shutdown keyword

[John Prather]

After wondering what to do to push this along, I realized that both
these patches are against the working 3.9.0 from prior to when it was
marked BROKEN.  I feel appropriately inept.

John Hein has been kind enough to forward me a patch for the 3.9.1
upgrade as well, which is now waiting on these fixes.

So I'm thinking, if nobody has started an attempt to commit this yet,
let's just scrap it.   Close out this PR and I will submit a new one
with:

a) rc script fixes
b) pkg-plist fixes
c) 3.9.1 upgrade

Any objections?

-john