localedef(1): Update license of 12 source files (CDDL => BSD2)

localedef(1): Update license of 12 source files (CDDL => BSD2)

The localdef sources were relicensed to 2-clause BSD by Illumos project
on 4 July 2014:

https://github.com/Nexenta/illumos-nexenta/commit/cf17542a37fc83d0ae093777e30d480423858c29

It was done for the benefit of the BSD community.  It is a nice gesture,
but I don't see this being much of a change.

1) The bundled avl files are still CDDL licensed, so that may spread to
   the entire program.

2) Even as CDDL, I didn't see this being an issue since localedef is
   self-contained so CDDL is limited to it.  (IANAL)