fix 'convert' with single commit repositories
The attached patch passes the three 'convert' testcases, and also is
able to successfully convert the git.git repository.
#!/bin/sh
hg init test
cd test
echo % Without -v
hg serve -a localhost -p 20063 -d --pid-file=hg.pid
cat hg.pid >> "$DAEMON_PIDS"
echo % With -v
hg serve -a localhost -p 20064 -d --pid-file=hg.pid -v
cat hg.pid >> "$DAEMON_PIDS"