loplugin:mergeclasses fix ignoring some stuff

Seems that calling getCanonicalDecl here results in us sometimes picking
up forward-decl's, which hides stuff

Also make the python processing code spit out a message if I manage to
mess up the log files

Change-Id: I08bf50eb26cf463c126507b51535b0a0fc9f7ecf

compilerplugins/clang/finalclasses.py

@@ -29,6 +29,9 @@ with open("workdir/loplugin.finalclasses.log") as txt:
                 parent = parent[7:]
             inheritFromSet.add(parent);
 
+        else:
+            print( "unknown line: " + line)
+
 tmpset = set()
 for clazz in sorted(definitionSet - inheritFromSet):
     file = definitionToFileDict[clazz]