libbb: disable a second md5 implementation which managed to creep in :)

libbb: disable a second md5 implementation which managed to creep in :)

function                                             old     new   delta
sha512_end                                           239     237      -2
sha256_end                                           162     160      -2
sha1_end                                             191     189      -2
md5_end                                              168     166      -2
__md5__magic                                           4       -      -4
md5_crypt                                            627     621      -6
static.S                                              16       -     -16
__md5_Init                                            42       -     -42
static.P                                              64       -     -64
__md5_Final                                          131       -    -131
__md5_Update                                         153       -    -153
static.C                                             268      12    -256
__md5_Transform                                      293       -    -293
------------------------------------------------------------------------------
(add/remove: 0/7 grow/shrink: 0/6 up/down: 0/-973)           Total: -973 bytes