Bug in Magic Money minting found

Here is code from near the end of mms_mint in s.c:

free(pc);
pgp_fix_mpi(&c->c);
f=fifo_file_create(fp);
fifo_put(MM_REGCOIN,f);
fifo_aput(pc->coinid,16,f);

pc is being freed but then used four lines later.  This is why the
coinid field was being corrupted in the output coins.dat file.  The
fix is to move the free to after the fifo_aput.