patman: add warning for invalid tag

Add a error in patman tool when the commit message contents an invalid
tag "Serie-.*" instead of "Series-.*".

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/patman/func_test.py b/tools/patman/func_test.py
index 1ce6448..9871bb5 100644
--- a/tools/patman/func_test.py
+++ b/tools/patman/func_test.py
@@ -506,6 +506,17 @@
             'Reviewed-by': {self.joe, self.mary},
             'Tested-by': {self.leb}})
 
+    def testInvalidTag(self):
+        """Test invalid tag in a patchstream"""
+        text = '''This is a patch
+
+Serie-version: 2
+'''
+        with self.assertRaises(ValueError) as exc:
+            pstrm = PatchStream.process_text(text)
+        self.assertEqual("Line 3: Invalid tag = 'Serie-version: 2'",
+                         str(exc.exception))
+
     def testMissingEnd(self):
         """Test a missing END tag"""
         text = '''This is a patch