binman: Allow listing an image created by a newer version

If an older version of binman is used to list images created by a newer
one, it is possible that it will contain entry types that are not
supported. At present this produces an error.

Adjust binman to use a plain 'blob' entry type to cope with this, so the
image can at least be listed.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/binman/entry_test.py

@@ -10,6 +10,7 @@ import sys
 import unittest
 
 from binman import entry
+from binman.etype.blob import Entry_blob
 from dtoc import fdt
 from dtoc import fdt_util
 from patman import tools
@@ -100,5 +101,13 @@ class TestEntry(unittest.TestCase):
         self.assertIn("Unknown entry type 'missing' in node '/binman/u-boot'",
                       str(e.exception))
 
+    def testMissingEtype(self):
+        """Test use of a blob etype when the requested one is not available"""
+        ent = entry.Entry.Create(None, self.GetNode(), 'missing',
+                                 missing_etype=True)
+        self.assertTrue(isinstance(ent, Entry_blob))
+        self.assertEquals('missing', ent.etype)
+
+
 if __name__ == "__main__":
     unittest.main()