context: rename troubled into isunstable
As we changed the meaning of unstable between the old vocabulary and the new
one, we can't reuse the unstable method name at the risk of breaking
extensions calling unstable and getting a wrong result.
Instead rename troubled into isunstable so extensions will continue to work.
The renaming is done according to
https://www.mercurial-scm.org/wiki/CEDVocabulary.
Differential Revision: https://phab.mercurial-scm.org/D242
Issue1678: IndexError when pushing
setting up base repo
$ hg init a
$ cd a
$ touch a
$ hg ci -Am a
adding a
$ cd ..
cloning base repo
$ hg clone a b
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd b
setting up cset to push
$ hg up null
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ touch a
different msg so we get a clog new entry
$ hg ci -Am b
adding a
created new head
pushing
$ hg push -f ../a
pushing to ../a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files (+1 heads)
$ cd ..