due to deduplication, it is intentionally impossible to
upload several identical copies of a file in parallel
by default, the up2k client will upload files sorted by
size, which usually leads to dupes being grouped together,
and it will try to do just that
this is by design, as it improves performance on average,
but it also shows the confusing (but technically-correct)
message "resume the partial upload into the original path"
fix this with a more appropriate message
note that this approach was selected in favor of pausing
handshakes while the initial copy finishes uploading,
because that could severely reduce upload performance
by preventing optimal use of multiple connections
f1130db131