Remove trailing spaces in debug log

We had a few trailing spaces in debug log.  My favorite pager (vim)
highlight trailing spaces with red characters which is slightly
annoying.

Change-Id: Ibd8aa4286d185b1b59d88352e68c6201a47e481d
diff --git a/tests/test_scheduler.py b/tests/test_scheduler.py
index f698d59..a953ffb 100755
--- a/tests/test_scheduler.py
+++ b/tests/test_scheduler.py
@@ -635,7 +635,7 @@
         self.fake_gerrit.addEvent(B.addApproval('APRV', 1))
         self.waitUntilSettled()
 
-        self.log.debug("len %s " % self.gerrit._change_cache.keys())
+        self.log.debug("len %s" % self.gerrit._change_cache.keys())
         # there should still be changes in the cache
         self.assertNotEqual(len(self.gerrit._change_cache.keys()), 0)