Ensure that presence state is decoded properly on Asterisk startup.

Ensure that presence state is decoded properly on Asterisk startup.

The CustomPresence provider callback will automatically base64 decode
stored data if the 'e' option was present when the state was set. However,
since the provider callback was bypassed on Asterisk startup, encoded
presence subtypes and messages were being sent instead. This fix makes
it so the provider callback is always used when providing presence
state updates.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@413469 65c4cc65-6c06-0410-ace0-fbb531ad65f3