push: When on an adjusted branch, propagate changes to parent branch before
updating export remotes.
This is a somewhat redundant call to propigateAdjustedCommits, since it
also gets called at pushLocal time. That other one needs to come after
importing from importtree remotes though, and seekExportContent has to come
earlier, so I don't see a way to avoid doing it twice.
Note that git-annex sync also manages to avoid the problem, it's only
git-annex push that had the bug.
Sponsored-by: Leon Schuermann on Patreon
