dirstate: clear map cached properties when clearing the map

dirstatemap.clear should remove all record of the files in the map.  This
includes removing caches of values derived from these.

Differential Revision: https://phab.mercurial-scm.org/D1338

mercurial/dirstate.py

@@ -1226,6 +1226,11 b' class dirstatemap(object):'
         self._map.clear()
         self.copymap.clear()
         self.setparents(nullid, nullid)
+        util.clearcachedproperty(self, "dirs")
+        util.clearcachedproperty(self, "filefoldmap")
+        util.clearcachedproperty(self, "dirfoldmap")
+        util.clearcachedproperty(self, "nonnormalset")
+        util.clearcachedproperty(self, "otherparentset")
 
     def iteritems(self):
         return self._map.iteritems()