hush: fix memory leak. it was actually rather invloved problem.

hush: fix memory leak. it was actually rather invloved problem.
Now finally glob/variable expansion is done IN THE RIGHT ORDER!
It opens up a possibility to cleanly fix remaining known bugs.

function                                             old     new   delta
o_save_ptr                                           115     286    +171
o_save_ptr_helper                                      -     115    +115
done_word                                            591     690     +99
o_get_last_ptr                                         -      31     +31
expand_on_ifs                                        125      97     -28
add_string_to_strings                                 28       -     -28
run_list                                            1895    1862     -33
debug_print_strings                                   42       -     -42
add_strings_to_strings                               126       -    -126
expand_variables                                    1550    1394    -156
o_debug_list                                         168       -    -168
expand_strvec_to_strvec                              388      10    -378
------------------------------------------------------------------------------
(add/remove: 2/4 grow/shrink: 2/4 up/down: 416/-959)         Total: -543 bytes