line editing: make read_line_input() not take timeout param

line editing: make read_line_input() not take timeout param

It's almost always -1.

function                                             old     new   delta
read_line_input                                     3902    3912     +10
new_line_input_t                                      24      31      +7
pgetc                                                583     585      +2
save_command_ps_at_cur_history                        80      78      -2
read_line                                             76      74      -2
fgetc_interactive                                    246     244      -2
addLines                                              84      82      -2
doCommands                                          2226    2222      -4
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/5 up/down: 19/-12)              Total: 7 bytes

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