kamiftp: remove unused variables

kamiftp: ensure compl_add_entry leaves a NULL terminator while here also rearrange a bit the compl_state_reset/compl_add_entry dance and do the allocations only in the latter.

kamiftp: add completions This adds completions when building with readline. kamiftp now completes command name, special arguments (on/off), local paths (default readline behaviour) and remote paths. This also tells readline how to handle quotes and escape characters.