buildhistory-collect-srcrevs: sort directories

In order to allow consistent output of buildhistory-collect-srcrevs sort
the list of directories returned by os.walk. Otherwise the list of
SRCREVs is returned in an unspecified order.

We save the output of this command on build, so it creates smaller diffs
between builds.

(From OE-Core rev: 3d7cb207ad4ec3cd5a3064147d3c9b5a1730d0fb)

Signed-off-by: Daniel McGregor <daniel.mcgregor@vecima.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/buildhistory-collect-srcrevs

@@ -59,6 +59,7 @@ def main():
 
     all_srcrevs = collections.defaultdict(list)
     for root, dirs, files in os.walk(options.buildhistory_dir):
+        dirs.sort()
         if '.git' in dirs:
             dirs.remove('.git')
         for fn in files: