keyword: (bugfix) only set changenode for kwtemplater when committing
kwexpand must always obtain changenode from filectx,
otherwise current changenode is expanded in every file.
Also fixes "hg cat <more than 1 file>".
#!/bin/sh
hg init
echo a > a
hg ci -Am t
hg mv a b
hg ci -Am t1
hg debugrename b
hg mv b a
hg ci -Am t2
hg debugrename a
echo % test with --rev
hg debugrename --rev 1 b