It was discovered on some Android systems, the stat size of a symlink
is different to the size that readlink returns.
This was giving errors like this
transport connection broken: http: ContentLength=30 with Body length 28
There are enough exceptions to the size of readlink being different to
the size of stat that this patch now always does readlink to work out
the size of a symlink.
Since symlinks are relatively uncommon this shouldn't affect
performance too much and will mean that the size is always correct.
This deprecates the --local-zero-size-links flag which is now
effectively always enabled.
See: https://forum.rclone.org/t/problem-with-symlinks-and-links/23840/
6ef7178ee4