bogotune bug in -v mode

[Matthias Andree]

David, Greg,

"bogotune -D -n gut -s schlecht -v" crashes here:

#7  0x0805d933 in rstats_fini (robn=6, P={mant = 9.2929390950634053e-05, exp = 0}, Q={mant = 0.0020635897044632388, exp = 0}, spamicity=0)
    at ../../src/rstats.c:121
#8  0x08054bea in msg_compute_spamicity (wh=0x811a030, fp=0x0) at ../../src/score.c:265
#9  0x0804a819 in score_ns (results=0x8c02db0) at ../../src/bogotune.c:369
#10 0x0804d363 in bogotune () at ../../src/bogotune.c:1606
#11 0x0804d852 in main (argc=0, argv=0x0) at ../../src/bogotune.c:1729

The problem is that stats_head is NULL. msg_compute_spamicity appears to
assumes it needs to run rstats_fini because verbose is set.

bogotune appears to give bogus results here, for instance:

db_cachesize=4
robs=1.0000
min_dev=0.020
robx=0.507000
sp_esf=0.866025
ns_esf=0.866025
spam_cutoff=0.000000    # for 0.00% fp (0); expect 0.00% fn (0).
ham_cutoff=0.450

I know too little about bogotune to fix the former and investigate the
latter. I tried training sets and unrelated mailboxes, same result, and
I get "No smooth minimum encountered, using lowest fn count"...

-- 
Matthias Andree