Before this change rclone was sending a MimeType in the requests for
server side Move and Copy.
The conjecture is that if you attempt to set the MimeType to something
different in a Copy then Google Drive has to do an actual copy of the
file data. This takes a very long time (since it is large) and fails
after a 90s timeout.
After the change we no longer set the MimeType in Move or Copy and the
copies happen instantly and correctly.
Many thanks to @darthShadow for discovering that this was causing the
problem.
Fixes#3070Fixes#3033Fixes#3300Fixes#3155
5433021e8b