Ryan McElroy <rmcelroy@fb.com> [Tue, 13 Oct 2015 03:20:05 -0700] rev 26671
rebase: factor out nothing to rebase return code
A rebase call that results in nothing to rebase might be considered successful
in some contexts. This factors out the return code from places where hg
determines that there is nothing to rebase, so an extenion might change this
return code to be something that would allow scripts to run without seeing this
as an error.