bug in perl installer that make UnixLink entries to be lost

the code in question try to re-assign entry that are in normal file
to links based on some condiftion... but when it did that
it would overwrite the content of the array that was passed
instead of adding to it, hence loosing any Unixlink entries.

Change-Id: Ia879dfefa4bf2fc635c05864b014e0712e51812d
Reviewed-on: https://gerrit.libreoffice.org/6574
Reviewed-by: David Tardon <dtardon@redhat.com>
Tested-by: David Tardon <dtardon@redhat.com>