Support showing one revision with Mercurial

* lisp/vc/vc-hg.el (vc-hg-print-log): Support 'with-diff'
invocation of "C-1 C-x v L".
1 job for master in 55 minutes and 18 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
failed #4386
test-all

00:55:18

 
Name Stage Failure
failed
test-all Test
make[2]: *** [check-doit] Error 1
Makefile:319: recipe for target 'check-doit' failed
make[2]: Leaving directory '/builds/emacs/emacs/test'
make[1]: *** [check-expensive] Error 2
Makefile:294: recipe for target 'check-expensive' failed
make[1]: Leaving directory '/builds/emacs/emacs/test'
make: *** [check-expensive] Error 2
Makefile:959: recipe for target 'check-expensive' failed
ERROR: Job failed: exit code 1