In order to send RADIUS accounting requests at the NAS level (for e.g.
Accounting-On/Off), radius_init() and radius_call() are made to accept a
null mac argument.
For radius_call() we fall back to the acct_session value (which is
required to be present per RFC) to construct the temporary file name.
Signed-off-by: Thibaut VARÈNE <hacks@slashdirt.org>
a647368f15