Default options are not properly read for GSIs

[sebdah]

Traceback (most recent call last):
File "/usr/local/bin/dynamic-dynamodb", line 22, in 
import dynamic_dynamodb
File "/usr/local/lib/python2.6/dist-packages/dynamic_dynamodb/init.py", line 29, in 
from dynamic_dynamodb.core import dynamodb, gsi, table
File "/usr/local/lib/python2.6/dist-packages/dynamic_dynamodb/core/dynamodb.py", line 12, in 
from dynamic_dynamodb.log_handler import LOGGER as logger
File "/usr/local/lib/python2.6/dist-packages/dynamic_dynamodb/log_handler.py", line 25, in 
import config_handler
File "/usr/local/lib/python2.6/dist-packages/dynamic_dynamodb/config_handler.py", line 4, in 
CONFIGURATION = config.get_configuration()
File "/usr/local/lib/python2.6/dist-packages/dynamic_dynamodb/config/init.py", line 121, in get_configuration
check_gsi_rules(configuration)
File "/usr/local/lib/python2.6/dist-packages/dynamic_dynamodb/config/__init.py", line 318, in __check_gsi_rules
if gsi['sns_message_types']:
KeyError: 'sns_message_types'