[Q] Have set-buffer-file-coding-system mark the buffer as modified.

[Stephen J. Turnbull]

QUERY

Aidan Kehoe writes:

 > APPROVE COMMIT
 > 
 > NOTE: This patch has been committed.

Since this patch has been committed, at least some of my non-ASCII
buffers initialize as "modified".  M-x revert-buffer does *not* clear
the modiff.

Please investigate and fix.