L::Data: Allow original-maintainer in all non-Debian profiles

Add a special instruction for data files that can be used to
conditionally add a line to a data file.  This instruction is now used
to allow the "original-maintainer" field when run under any
"non-Debian" profile (that inherits from the Debian profiles).

Signed-off-by: Niels Thykier <niels@thykier.net>