setdiscovery: return anyincoming=False when remote's only head is nullid This fixes (issue2907) a crash when using 'hg incoming --bundle' with an empty remote repo and a non-empty local repo. This also fixes an unreported bug that 'hg summary --remote' erroneously reports incoming changes when the remote repo is empty and the local is not. Also, add a test to make sure issue2907 stays fixed

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init

  $ echo 'base' > base
  $ hg ci -Ambase
  adding base

  $ hg qnew -mmqbase mqbase

  $ hg qsave
  $ hg qrestore 2
  restoring status: hg patches saved state