This new histedit command (short for "rollup") is a variant of "fold" akin to
"hg amend" for working copy: it accumulates changes without interrupting
the user and asking for an updated commit message.
Before this patch, if there are multiple roots in "--outgoing"
revisions, result of "histedit --outgoing" depends on the parent of
the working directory. It succeeds only when the parent of the working
directory is a descendant of the oldest root in "--outgoing"
revisions, and fails otherwise.
It seems to be ambiguous and difficult for users.
This patch makes "histedit --outgoing" abort if there are multiple
roots in "--outgoing" revisions always.
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.
