Replace backticks with repr() or "%r"

From SF patch #852334.
diff --git a/Lib/sunaudio.py b/Lib/sunaudio.py
index 86a5b41..3b0ee27 100644
--- a/Lib/sunaudio.py
+++ b/Lib/sunaudio.py
@@ -41,4 +41,4 @@
     print 'Encoding:   ', encoding
     print 'Sample rate:', sample_rate
     print 'Channels:   ', channels
-    print 'Info:       ', `info`
+    print 'Info:       ', repr(info)