Use fallback MMS attachment name if can’t create file with received name

Received MMS location may be encoded using RFC 2047 (e.g. for messages
sent from old Nokia phones) or may contain characters illegal in file names.
RFC 2047 decoding is currently not implemented so fallback name
should be used in such case. I also changed fallback name to be
a human readable localized text instead of hex message id.

Backported from CM Jellybean branch