convert: svn -- fix 'exists' Previously 'exists' erroneously returned False for empty dirictories. This is wrong since we want to detect even empty 'branches/' or 'tags/'.

#!/bin/sh

hg init a
echo a > a/a
hg --cwd a ci -A -m a
hg clone a b
echo b > b/b
hg --cwd b ci -A -m b
chmod 100 a/.hg/store
hg --cwd b push ../a
chmod 700 a/.hg/store