convert all blobs to bytea

MySQL has not only blob but also mediumblob, longblob and stuff. Let's catch them all.

db_converter.py

@@ -136,7 +136,7 @@ def parse(input_filename, output_filename):
                     type = "timestamp with time zone"
                 elif type == "double":
                     type = "double precision"
-                elif type == "blob":
+                elif type.endswith("blob"):
                     type = "bytea"
                 elif type.startswith("enum(") or type.startswith("set("):