persist_data: raise KeyError on missing elements

(Bitbake rev: a4f62433845c29f98c6a9746d5d2847bf9506ea5)

Signed-off-by: Chris Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/fetch/git.py

@@ -246,18 +246,20 @@ class Git(Fetch):
         revs = persisted['BB_URI_HEADREVS']
 
         key = self.generate_revision_key(url, ud, d, branch=True)
-        rev = revs[key]
-        if rev is None:
+
+        try:
+            return revs[key]
+        except KeyError:
             # Compatibility with old key format, no branch included
             oldkey = self.generate_revision_key(url, ud, d, branch=False)
-            rev = revs[oldkey]
-            if rev is not None:
-                del revs[oldkey]
-            else:
+            try:
+                rev = revs[oldkey]
+            except KeyError:
                 rev = self._latest_revision(url, ud, d)
+            else:
+                del revs[oldkey]
             revs[key] = rev
-
-        return str(rev)
+            return rev
 
     def sortable_revision(self, url, ud, d):
         """