use spaces to indent instead of tabs

tools/list-sn-spec.py

@@ -5,7 +5,7 @@ import sys
 def main():
     sn = sys.argv[1]
     for k in range(1, 21):
-    	print 'r%d' % k + '---' + 'sn-' + sn + '.googlevideo.com'
+        print 'r%d' % k + '---' + 'sn-' + sn + '.googlevideo.com'
 
 if __name__ == '__main__':
     main()