Follow symlinks in findleaves

If we replace the project directories with symlinks to the actual
directories, everything should build fine.  Unfortunately, without
this fix, it does not.

Change-Id: Id19fef9696d0f599a7b3a14b6a8fc10ae857f9c7
diff --git a/tools/findleaves.py b/tools/findleaves.py
index 52c4d9f..3a9e508 100755
--- a/tools/findleaves.py
+++ b/tools/findleaves.py
@@ -28,7 +28,7 @@
   pruneleaves = set(map(lambda x: os.path.split(x)[1], prune))
   for rootdir in dirlist:
     rootdepth = rootdir.count("/")
-    for root, dirs, files in os.walk(rootdir):
+    for root, dirs, files in os.walk(rootdir, followlinks=True):
       # prune
       check_prune = False
       for d in dirs: