children extension: Don't abort when looking at the null revision.
Since 62c56d8f368b revlog.children only returns real children,
so this is no longer a problem.
#!/bin/sh
mkdir t
cd t
hg init
mkdir a
echo foo > a/a
echo bar > a/b
hg add a
hg ci -m "0" -d "0 0"
hg co -C 0
hg mv a b
hg ci -m "1 mv a/ b/" -d "0 0"
hg co -C 0
echo baz > a/c
hg add a/c
hg ci -m "2 add a/c" -d "0 0"
hg merge --debug 1
echo a/* b/*
hg st -C
hg ci -m "3 merge 2+1" -d "0 0"
hg co -C 1
hg merge --debug 2
echo a/* b/*
hg st -C
hg ci -m "4 merge 1+2" -d "0 0"