obsutil: don't assume leftctx and rightctx repo as same Backed out changeset 520514af2d93. hgsubversion can pass leftctx and rightctx which are instances of two different repositories. This was making tests fail on hgsubversion with 4.9. The two different instances are: (Pdb) p rightctx.repo() <filteredrepo:served <hgsubversion.svnrepo.svnlocalrepo object at 0x7fe29d296d10>> (Pdb) p leftctx.repo() <filteredrepo:visible <hgsubversion.svnrepo.svnlocalrepo object at 0x7fe29d494590>> Differential Revision: https://phab.mercurial-scm.org/D5968