Added some warning filters.

 - Legacy-Id: 16390

Author: levkowetz

ietf/settings.py

@@ -25,6 +25,8 @@
 warnings.filterwarnings("ignore", message="Duplicate index '.*' defined on the table")
 # Warnings found under Python 3.7:
 warnings.filterwarnings("ignore", message="'U' mode is deprecated", module="docutils.io")
+warnings.filterwarnings("ignore", message="'U' mode is deprecated", module="xml2rfc")
+warnings.filterwarnings("ignore", message="Flags not at the start of the expression", module="genshi")
 
 
 try: