histedit: make "hg histedit" sensitive to branch in URL

Before this patch, "hg histedit" are not sensitive to the branch
specified in the URL of the destination repository, even though "hg
push"/"hg outgoing" are so:

Invocation of "discovery.findcommonoutgoing()" without "onlyheads"
argument treats revisions on branches other than the one specified in
the URL as outgoing ones unexpectedly.

This patch specifies list of head revisions, which are already
detected by "hg.addbranchrevs()" from URL and looked up against local
repository, as "onlyheads" to "discovery.findcommonoutgoing()" to
limit calculation of outgoing revisions.

hgext/histedit.py

@@ -459,7 +459,7 b' def histedit(ui, repo, *parent, **opts):'
         # contains special revset characters like ":" the revset
         # parser can choke.
         parent = [node.hex(n) for n in discovery.findcommonoutgoing(
-            repo, other, [], force=opts.get('force')).missing[0:1]]
+            repo, other, revs, force=opts.get('force')).missing[0:1]]
     else:
         if opts.get('force'):
             raise util.Abort(_('--force only allowed with --outgoing'))

tests/test-histedit-outgoing.t

@@ -82,3 +82,24 b' show the error from unrelated repos'
   #
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cd ..
+
+test sensitivity to branch in URL:
+
+  $ cd r2
+  $ hg -q update 2
+  $ hg -q branch foo
+  $ hg commit -m 'create foo branch'
+  $ HGEDITOR=cat hg histedit --outgoing '../r#foo' | grep -v comparing | grep -v searching
+  pick f26599ee3441 6 create foo branch
+  
+  # Edit history between f26599ee3441 and f26599ee3441
+  #
+  # Commands:
+  #  p, pick = use commit
+  #  e, edit = use commit, but stop for amending
+  #  f, fold = use commit, but fold into previous commit (combines N and N-1)
+  #  d, drop = remove commit from history
+  #  m, mess = edit message without changing commit content
+  #
+  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ cd ..