Set `is_bash` for `sh.vim`.

Even when writing old-timey Bourne shell to satisfy FreeBSD, there are
constructs that `is_bash` permits that `is_sh` highlights in erroneous
red, so I'm going to default to `is_bash` even though I'm not often
writing actual bash code.
Build certs for Postfix on OS X.

Building certificates from the Mozilla CA bundle using the bundle
builder Perl script that comes with cURL. Building the bundle requires
downloading cURL, verifying the latest release with its GnuPG key, and
then downloading the certificate data from from Mozilla and building the
cert bundle file.

cURL is hosted via HTTP. I verify it using Daniel Stenberg's GnuPG key,
which I've added to this repository. The certificate data is downloaded
from Mozilla via HTTPs.