Replace backticks with repr() or "%r"

From SF patch #852334.
diff --git a/Demo/rpc/rnusersclient.py b/Demo/rpc/rnusersclient.py
index e9cad62..90cbd6d 100644
--- a/Demo/rpc/rnusersclient.py
+++ b/Demo/rpc/rnusersclient.py
@@ -77,7 +77,7 @@
 		line = strip0(line)
 		name = strip0(name)
 		host = strip0(host)
-		print `name`, `host`, `line`, time, idle
+		print "%r %r %r %s %s" % (name, host, line, time, idle)
 
 def testbcast():
 	c = BroadcastRnusersClient('<broadcast>')