tests/test-mq-subrepo-svn.t

discovery: drop findoutgoing and simplify findcommonincoming's api

This is a long desired cleanup and paves the way for new discovery.
To specify subsets for bundling changes, all code should use the heads
of the desired subset ("heads") and the heads of the common subset
("common") to be excluded from the bundled set. These can be used
revlog.findmissing instead of revlog.nodesbetween.

This fixes an actual bug exposed by the change in test-bundle-r.t
where we try to bundle a changeset while specifying that said changeset
is to be assumed already present in the target. This used to still
bundle the changeset. It no longer does. This is similar to the bugs
fixed by the recent switch to heads/common for incoming/pull.

  $ "$TESTDIR/hghave" svn || exit 80

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH
  $ echo "[diff]" >> $HGRCPATH
  $ echo "nodates=1" >> $HGRCPATH

fn to create new repository, and cd into it
  $ mkrepo() {
  >     hg init $1
  >     cd $1
  >     hg qinit
  > }


handle svn subrepos safely

  $ svnadmin create svn-repo-2499
  $ curpath=`pwd | tr '\\\\' /`
  $ expr "$svnpath" : "\/" > /dev/null
  > if [ $? -ne 0 ]; then
  >   curpath="/$curpath"
  > fi
  $ svnurl="file://$curpath/svn-repo-2499/project"
  $ mkdir -p svn-project-2499/trunk
  $ svn import -m 'init project' svn-project-2499 "$svnurl"
  Adding         svn-project-2499/trunk
  
  Committed revision 1.

qnew on repo w/svn subrepo
  $ mkrepo repo-2499-svn-subrepo
  $ svn co "$svnurl"/trunk sub
  Checked out revision 1.
  $ echo 'sub = [svn]sub' >> .hgsub
  $ hg add .hgsub
  $ hg status -S -X '**/format'
  A .hgsub
  ? sub/.svn/entries
  $ hg qnew -m0 0.diff
  committing subrepository sub
  $ cd sub
  $ echo a > a
  $ svn add a
  A         a
  $ svn st
  A*    a (glob)
  $ cd ..
  $ hg status -S        # doesn't show status for svn subrepos (yet)
  $ hg qnew -m1 1.diff
  abort: uncommitted changes in subrepository sub
  [255]