Replace backticks with repr() or "%r"

From SF patch #852334.
diff --git a/Lib/test/test_poll.py b/Lib/test/test_poll.py
index ed1d736..2ecae69 100644
--- a/Lib/test/test_poll.py
+++ b/Lib/test/test_poll.py
@@ -157,7 +157,7 @@
         elif flags & select.POLLIN:
             line = p.readline()
             if verbose:
-                print `line`
+                print repr(line)
             if not line:
                 if verbose:
                     print 'EOF'