tests/test-commit-copy

keyword: pass context to kwtemplater.overwrite

Now that we have retrieved the context in every calling function
except commit, pass it as argument to kwtemplater.overwrite to
avoid looking it up twice.

Reorder arguments to kwtemplater.overwrite to reflect their
importance.

Turn node argument into a simple boolean and rename it to iswctx.

#!/bin/sh

hg init dir
cd dir
echo bleh > bar
hg add bar
hg ci -m 'add bar'

hg cp bar foo
echo >> bar
hg ci -m 'cp bar foo; change bar'

hg debugrename foo
hg debugindex .hg/store/data/bar.i