rpm: code shrink

rpm: code shrink

function                                             old     new   delta
rpm_getstr0                                            -       7      +7
rpm_getstr                                           112     110      -2
rpm_getint                                           120     118      -2
bsearch_rpmtag                                        15      13      -2
shell_builtin_read                                  1334    1320     -14
rpm_main                                            1548    1474     -74
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/5 up/down: 7/-94)             Total: -87 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>