Ensure deserialization of session data always returns non-None object.
Ensure deserialization of session data always returns non-None object.

When deserializing invalid session data, such as an expired session,
the `_get_data()` method sometimes returns None. This fix ensures that
the `data` property always returns an empty dict instead of None in this
and all cases, to avoid breaking subsequent get lookups of the session
data.

kshitizanand/authomatic,leadbrick/authomatic,artitj/authomatic,scorphus/authomatic,dougchestnut/authomatic,garg91824/authomatic,liorshahverdi/authomatic,farcaz/authomatic,dougchestnut/authomatic,touilleMan/authomatic,leadbrick/authomatic,peterhudec/authomatic,kshitizanand/authomatic,farcaz/authomatic,dougchestnut/authomatic,farcaz/authomatic,dougchestnut/authomatic,jasco/authomatic,daherk2/authomatic,touilleMan/authomatic,leadbrick/authomatic,liorshahverdi/authomatic,scorphus/authomatic,c24b/authomatic,daherk2/authomatic,touilleMan/authomatic,artitj/authomatic,authomatic/authomatic,erasanimoulika/authomatic,c24b/authomatic,authomatic/authomatic,peterhudec/authomatic,muravjov/authomatic,farcaz/authomatic,authomatic/authomatic,scorphus/authomatic,c24b/authomatic,kshitizanand/authomatic,garg91824/authomatic,erasanimoulika/authomatic,muravjov/authomatic,farcaz/authomatic,liorshahverdi/authomatic,peterhudec/authomatic,scorphus/authomatic,jasco/authomatic,vivek8943/authomatic,muravjov/authomatic,jasco/authomatic,leadbrick/authomatic,vivek8943/authomatic,touilleMan/authomatic,vivek8943/authomatic,dougchestnut/authomatic,leadbrick/authomatic,daherk2/authomatic,scorphus/authomatic,artitj/authomatic,erasanimoulika/authomatic,garg91824/authomatic