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
python -c 'print "confuse str.splitlines\nembedded\rnewline"' > a
hg ci -Ama -d '1 0'
echo clean diff >> a
hg ci -mb -d '2 0'
hg diff -r0 -r1