ancestor: remove now-unused missingancestors function

Callers should use revlog.incrementalmissingrevs instead.

mercurial/ancestor.py

@@ -220,10 +220,6 b' class incrementalmissingancestors(object'
         missing.reverse()
         return missing
 
-def missingancestors(revs, bases, pfunc):
-    inc = incrementalmissingancestors(pfunc, bases)
-    return inc.missingancestors(revs)
-
 class lazyancestors(object):
     def __init__(self, pfunc, revs, stoprev=0, inclusive=False):
         """Create a new object generating ancestors for the given revs. Does