Reintroduce what we fixed in 08a68bb4a02376905be136d3cafb14bc7cbc3098
and reverted in 2d79191c97e8ee965bfea1feef03de26c839dc8a. rsync(1)
source files that contain colons (":") need to be prefixed with "./" to
ensure rsync(1) doesn't interpret them as remote modules.
The conditional branching is needed since we might use "$PKGDEST"
(resulting in absolute package paths).
Reported-by: Alexander Rødseth