shell: do not read user database for every prompt - only for those which need it

function                                             old     new   delta
get_user_strings                                       -      52     +52
get_homedir_or_NULL                                    -      23     +23
parse_and_put_prompt                                 823     838     +15
null_str                                               1       -      -1
complete_cmd_dir_file                                814     812      -2
deinit_S                                              51      42      -9
read_line_input                                     3059    3015     -44
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(add/remove: 2/1 grow/shrink: 1/3 up/down: 90/-56)             Total: 34 bytes

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