[1333r] revised comment wording a bit.

src/lib/python/isc/datasrc/tests/datasrc_test.py

@@ -694,7 +694,7 @@ class JournalRead(unittest.TestCase):
         self.reader = None
 
     def tearDown(self):
-        # Some test leaves the reader in the middle of sequence, holding
+        # Some tests leave the reader in the middle of sequence, holding
         # the lock.  Since the unittest framework keeps each test object
         # until the end of the entire tests, we need to make sure the reader
         # is released at the end of each test.  The client shouldn't do harm