Remove non-existent Kconfig symbol references. An additional (but
related) change is the removal of all persistent storage symbols from
the Arduino 101 Bluetooth shell app, since BT_STORAGE no longer
exists.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The conf file name must be of the form prj_<board>.conf for it to be
automatically chosen for a given board.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>