Added validation to blind detection

Included checks for any ring game hands if there's a blind could be
found and if either SB or BB detection fails then determineGameType will
return None. It's needed for handling some invalid ring hands (e.g.
table closed messages at the end of a HH file).

Signed-off-by: steffen123 <steffen@schaumburger.info>

pyfpdb/PartyPokerToFpdb.py

@@ -219,6 +219,9 @@ class PartyPoker(HandHistoryConverter):
             info['type'] = 'ring'
 
         if info['type'] == 'ring':
+            if (m_sb is None) or (m_bb is None):
+                return None
+            else:
                 info['sb'] = m_sb.group('RINGSB')
                 info['bb'] = m_bb.group('RINGBB')
             info['currency'] = currencies[mg['CURRENCY']]