obsolete: fix old typo

Clean an old typo in successorssets.

Differential Revision: https://phab.mercurial-scm.org/D531

mercurial/obsutil.py

@@ -562,9 +562,9 b' def successorssets(repo, initialnode, cl'
                 # remove duplicated and subset
                 seen = []
                 final = []
-                candidate = sorted((s for s in succssets if s),
-                                   key=len, reverse=True)
-                for cand in candidate:
+                candidates = sorted((s for s in succssets if s),
+                                    key=len, reverse=True)
+                for cand in candidates:
                     for seensuccs in seen:
                         if cand.canmerge(seensuccs):
                             seensuccs.markers.update(cand.markers)