Using stdio for tradspool.map causes problems

[eagle]

The code in tradspool to write out tradspool.map uses stdio, which can cause problems if innd has already consumed a lot of file descriptors. On a lot of 32-bit systems, stdio can only handle file descriptors below 256. innd has code to deal with this, but tradspool doesn't.

The easiest solution is to probably avoid using stdio when writing out tradspool.