Rework the logic for fetching TA files a bit. Move the logic that checks

Rework the logic for fetching TA files a bit. Move the logic that checks
if all possible sources have been used to ta_fetch() this simplifies the
logic in the rsync and http done cases.
Additionally when -R is used, skip https URI and only connect via rsync.
If the TAL file has no rsync URI then the system will fall back to the
cache and not try https instead.
This makes -R a only use rsync flag.
With and OK job@