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
echo This is file a1 > a
hg add a
hg commit -m "commit #0" -d "1000000 0"
touch b
hg add b
rm b
hg commit -A -m"comment #1" -d "1000000 0"