test_missing_obj_finder: fix bogus haves test

The code under test states in a comment that non-local haves are legal,
but that non-local wants are not. The test was attempting to enforce
that both non-local haves and wants were not legal, but was getting
lucky due to an error in the test implementation.

The bogus wants test is fixed in the following commit.

dulwich/tests/test_missing_obj_finder.py

@@ -91,13 +91,12 @@ class MOFLinearRepoTest(MissingObjectFinderTest):
         self.assertMissingMatch([self.cmt(1).id], [self.cmt(3).id],
             self.missing_1_3)
 
-    def test_bogus_haves_failure(self):
-        """Ensure non-existent SHA in haves are not tolerated"""
+    def test_bogus_haves(self):
+        """Ensure non-existent SHA in haves are tolerated"""
         bogus_sha = self.cmt(2).id[::-1]
         haves = [self.cmt(1).id, bogus_sha]
         wants = [self.cmt(3).id]
-        self.assertRaises(KeyError, self.store.find_missing_objects,
-            self.store, haves, wants)
+        self.assertMissingMatch(haves, wants, self.missing_1_3)
 
     def test_bogus_wants_failure(self):
         """Ensure non-existent SHA in wants are not tolerated"""