agetty: make username-in-uppercase feature optional (off by default.)

agetty: make username-in-uppercase feature optional (off by default.)

The following patch makes the username-in-upper-case feature optional.

I have chosen to make it default to off since this feature was designed
to cater for serial terminals that were last sold almost 30 years ago,
thus the likelyhood that anyone will need this feature turned on is
vanishingly small.

Addresses-Debian-Bug: 156242
Signed-off-by: Hamish Coleman <hamish@zot.org>
Signed-off-by: LaMont Jones <lamont@debian.org>
Signed-off-by: Karel Zak <kzak@redhat.com>