Treat same checksum and size as the same version

This can happen if the url for downloading changed (i.e. load-balancing), but the actual application is still the same.

src/lib/externaldata.py

@@ -320,8 +320,7 @@ def matches(self, other: ExternalFile):
         for i in (self, other):
             assert i.checksum is None or isinstance(i.checksum, MultiDigest), i.checksum
         return (
-            self.url == other.url
-            and self.checksum == other.checksum
+            self.checksum == other.checksum
             and (self.size is None or other.size is None or self.size == other.size)
         )