Replace backticks with repr() or "%r"

From SF patch #852334.
diff --git a/Lib/plat-irix5/cdplayer.py b/Lib/plat-irix5/cdplayer.py
index 278da03..3cbd0d8 100755
--- a/Lib/plat-irix5/cdplayer.py
+++ b/Lib/plat-irix5/cdplayer.py
@@ -82,8 +82,7 @@
 		new.write(self.id + '.title:\t' + self.title + '\n')
 		new.write(self.id + '.artist:\t' + self.artist + '\n')
 		for i in range(1, len(self.track)):
-			new.write(self.id + '.track.' + `i` + ':\t' + \
-				  self.track[i] + '\n')
+			new.write('%s.track.%r:\t%s\n' % (self.id, i, self.track[i])
 		old.close()
 		new.close()
 		posix.rename(filename + '.new', filename)