Replace backticks with repr() or "%r"

From SF patch #852334.
diff --git a/Lib/plat-irix6/panel.py b/Lib/plat-irix6/panel.py
index f8388c6..3aa7448 100644
--- a/Lib/plat-irix6/panel.py
+++ b/Lib/plat-irix6/panel.py
@@ -127,7 +127,7 @@
 				ok = 0
 			if ok:
 				lhs = 'target.' + prefix + name
-				stmt = lhs + '=' + `value`
+				stmt = lhs + '=' + repr(value)
 				if debug: print 'exec', stmt
 				try:
 					exec stmt + '\n'