Check for state before disconnecting.

This is a race condition exposed after we turned off some STOPSHIP
logging and some other logging. We drop the ACl connection after 2 secs
of inactivity and hence the device didn't exist -> DBUS crash.

Bug: 3097224
Change-Id: I90adbbee2c5793924037685e484027ed5cd2e0d0
1 file changed