test-convert-darcs: skip if we can't find the elementtree module
This patch is a bit dirty to avoid having to repeat the dance required
to import elementtree.
#!/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