selftest/bblayers: adjust the revision for the layer setup test

Using a tag is not actually robust enough, e.g. poky-contrib
checkouts do not come with any tags. So let's use a revision
matching yocto-4.0, that ought to be present.

(From OE-Core rev: 1246aa8e4c9e6fce2f7700cd8e8ad9566a21d6e3)

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/selftest/cases/bblayers.py

@@ -149,12 +149,12 @@ class BitbakeLayers(OESelftestTestCase):
         self.validate_layersjson(jsonfile)
 
         # The revision-under-test may not necessarily be available on the remote server,
-        # so replace it with a stable release tag.
+        # so replace it with a revision that has a yocto-4.0 tag.
         import json
         with open(jsonfile) as f:
             data = json.load(f)
         for s in data['sources']:
-            data['sources'][s]['git-remote']['rev'] = 'yocto-4.0'
+            data['sources'][s]['git-remote']['rev'] = '00cfdde791a0176c134f31e5a09eff725e75b905'
         with open(jsonfile, 'w') as f:
             json.dump(data, f)