sparse: clear rules in the context of a `parentchanges` context

This is the same logic as the change we did for narrow.

Differential Revision: https://phab.mercurial-scm.org/D11029

mercurial/sparse.py

@@ -630,7 +630,7 b' def clearrules(repo, force=False):'
     The remaining sparse config only has profiles, if defined. The working
     directory is refreshed, as needed.
     """
-    with repo.wlock():
+    with repo.wlock(), repo.dirstate.parentchange():
         raw = repo.vfs.tryread(b'sparse')
         includes, excludes, profiles = parseconfig(repo.ui, raw, b'sparse')
 
@@ -708,7 +708,7 b' def updateconfig('
 
     The new config is written out and a working directory refresh is performed.
     """
-    with repo.wlock():
+    with repo.wlock(), repo.dirstate.parentchange():
         raw = repo.vfs.tryread(b'sparse')
         oldinclude, oldexclude, oldprofiles = parseconfig(
             repo.ui, raw, b'sparse'