vc behaves differently in 21.5 and 21.4

[Stephen J. Turnbull]

Uwe Brauer writes:

 > Which results  for 21.4.22 in a file 
 > 
 >  test-rev.tex
 > 
 > However it does not work in 21.5.19. 
 > It results in test.tex~rev~!
 > 
 > I tried to debug the function and the error seems here

    (let ((filename (concat (file-name-sans-extension buffer-file-name)
                            "-rev-"
                            version
                            "."
                            (file-name-extension buffer-file-name))))

There is no way this can produce "test.tex~rev~", even if both
`file-name-sans-extension' and `file-name-extension' are broken:  the
literal string "-rev-" must be present.

So somehow your function is apparently not being called.