ast_device_state() gets called in two different ways. The first way is when

ast_device_state() gets called in two different ways.  The first way is when
called from elsewhere in Asterisk to find the current state of a device.  In
that case, we want to use the cached value if it exists.  The other way is when
processing a device state change.  In that case, we do not want to check the
cache because returning the last known state is counter productive.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@133945 65c4cc65-6c06-0410-ace0-fbb531ad65f3