vi: remove duplicated code

vi: remove duplicated code

At worst show_status_line() might be called needlessly when the
user presses ^L/^R, but I don't think we'll get many complaints
about that.

function                                             old     new   delta
do_cmd                                              4592    4558     -34
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-34)             Total: -34 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>