dpkg: fix creation of .list files (were empty since b768aeb). Closes 5324

dpkg: fix creation of .list files (were empty since b768aeb). Closes 5324

While at it, fix filename order and free the list of names.

function                                             old     new   delta
llist_rev                                              -      21     +21
get_header_tar                                      1733    1741      +8
unpack_package                                       587     585      -2
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(add/remove: 1/0 grow/shrink: 1/1 up/down: 29/-2)              Total: 27 bytes

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