evolvecmd: _possibledestination() skip visiting empty parent
I see that even in the case when "parent == -1" we are visiting
that also and find succsets for that and in last -1 is being
added in the set of possible destination. Why not skip that?
#!/bin/sh
. $TESTDIR/testlib/pythonpath.sh
# This file holds logic that is used in many tests.
# It can be called in a test like this:
# $ . "$TESTDIR/testlib/topic_setup.sh"
# Enable obsolete markers and enable extensions
cat >> $HGRCPATH << EOF
[experimental]
evolution=createmarkers,exchange
[extensions]
rebase=
topic=
EOF