Removing default '' return for ast_args_to_str()
Removing default '' return for ast_args_to_str()

This removes a default return value for ast_args_to_str() that was
an development stub artifact.  Additional work may be needed to clean
this function up but will leave it returning something for now.

Change-Id: I99904a49358097728de27051bae65791822f2f3e

pombredanne/bandit,pombredanne/bandit,austin987/bandit,stackforge/bandit,chair6/bandit,stackforge/bandit