convert: use manifest.diff() instead of ctx.status()

mercurial_source.getchanges() seems to care about files whose nodeid
has changed even if their contents has not (i.e. it has been
reverted/backed out). The method uses ctx1.status(ctx2) to find
differencing files. However, that method is currently broken and
reports reverted changes as modified. In order to fix that method, we
first need to rewrite getchanges() using manifest.diff(), which does
report reverted files as modified (because it's about differences in
the manifest, so about nodeids).

hgext/convert/hg.py

@@ -508,8 +508,16 b' class mercurial_source(converter_source)'
             return None, None
 
     def _changedfiles(self, ctx1, ctx2):
-        m, a, r = ctx1.status(ctx2)[:3]
-        return (m + a, r)
+        ma, r = [], []
+        maappend = ma.append
+        rappend = r.append
+        d = ctx1.manifest().diff(ctx2.manifest())
+        for f, ((node1, flag1), (node2, flag2)) in d.iteritems():
+            if node2 is None:
+                rappend(f)
+            else:
+                maappend(f)
+        return ma, r
 
     def getchanges(self, rev, full):
         ctx = self._changectx(rev)
@@ -529,8 +537,10 b' class mercurial_source(converter_source)'
         copies = self._getcopies(ctx, parents, copyfiles)
         cleanp2 = set()
         if len(parents) == 2:
-            cleanp2.update(self.repo.status(parents[1].node(), ctx.node(),
-                                            clean=True).clean)
+            d = parents[1].manifest().diff(ctx.manifest(), clean=True)
+            for f, value in d.iteritems():
+                if value is None:
+                    cleanp2.add(f)
         changes = [(f, rev) for f in files if f not in self.ignored]
         changes.sort()
         return changes, copies, cleanp2