*: get rid of "MTYPE 0"

*: get rid of "MTYPE 0"

A few places are using 0 in place of the MTYPE_* argument.  The
following rewrite of the alloc tracking won't deal with that, so let's
use MTYPE_TMP instead.

Acked-by: Vincent JARDIN <vincent.jardin@6wind.com>
Acked-by: Donald Sharp <sharpd@cumulusnetworks.com>
[DL: v2: fix XFREE(0, foo) calls too]
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>