Fix bug when raw files are empty.

src/ng6/t3MySQLdb.py

@@ -301,9 +301,9 @@ class t3MySQLdb(object):
             req += "data_nature='" + data_nature.replace("'", "\'") + "',"
         if type:
             req += "type='" + type.replace("'", "\'") + "',"
-        if nb_sequences:
+        if nb_sequences is not None:
             req += "nb_sequences='" + str(nb_sequences) + "',"
-        if full_seq_size:
+        if full_seq_size is not None:
             req += "full_seq_size='" + str(full_seq_size) + "',"
         if description:
             req += "description='" + str(description.replace("'", "\'")) + "',"