Sort the results of findleaves again.

Commit d36e945 changed findleaves.py to sort the output files so that
the order is deterministic and won't cause spurious build errors when
files happen to be listed (and hence read) in different order on
e.g. add/remove the makefiles.

This correction broke after commit 4820a94 because the conversion to
a set with set() in order to remove duplicates came after sort() and
potentially altered the order of the elements.

This commit fixes makes sure findleaves.py is guaranteed to return
a sorted filename list without duplicates.

Change-Id: Ifd96d04d45641fe43d4cc4739f78a2d4d25cc212
diff --git a/tools/findleaves.py b/tools/findleaves.py
index 0adf188..52c4d9f 100755
--- a/tools/findleaves.py
+++ b/tools/findleaves.py
@@ -89,9 +89,9 @@
     usage()
   dirlist = argv[i:-1]
   filename = argv[-1]
-  results = perform_find(mindepth, prune, dirlist, filename)
+  results = list(set(perform_find(mindepth, prune, dirlist, filename)))
   results.sort()
-  for r in set(results):
+  for r in results:
     print r
 
 if __name__ == "__main__":