Fix: device can not power off due to crash

Fix: device can not power off due to crash

system_server crash at power off the phone. See below back trace.

 Program terminated with signal 11, Segmentation fault.
 #0  0xb76a898f in _unregister_noti (key=0xb451e1f8, value=0xb450a6b0,
    user_data=0x0) at
 /usr/src/debug/libslp-tapi-0.6.69/src/tapi_common.c:1290
 1290
 g_dbus_connection_signal_unsubscribe(handle->dbus_connection,
 evt_cb_data->evt_id);
 (gdb) bt
 #0  0xb76a898f in _unregister_noti (key=0xb451e1f8, value=0xb450a6b0,
    user_data=0x0) at
 /usr/src/debug/libslp-tapi-0.6.69/src/tapi_common.c:1290
 #1  0xb74518a9 in g_hash_table_foreach_remove_or_steal ()
   from /usr/lib/libglib-2.0.so.0
 #2  0xb76ad3c5 in tel_deinit (handle=0x8d14e48)
    at /usr/src/debug/libslp-tapi-0.6.69/src/tapi_common.c:1304
 #3  0x08050ff4 in powerdown_ap_by_force (data=0x0)
    at /usr/src/debug/system-server-0.1.65/ss_predefine.c:324
 #4  0xb779c38a in _ecore_timer_expired_call () from
 /usr/lib/libecore.so.1
 #5  0xb779c557 in _ecore_timer_expired_timers_call ()
   from /usr/lib/libecore.so.1
 #6  0xb7798d13 in _ecore_main_loop_iterate_internal ()
   from /usr/lib/libecore.so.1
 #7  0xb779941f in ecore_main_loop_begin () from /usr/lib/libecore.so.1
 #8  0x0804bd45 in system_main (argc=1, argv=0xbfb6f154)
    at /usr/src/debug/system-server-0.1.65/ss_main.c:102
 #9  0x0804bda1 in elm_main (argc=1, argv=0xbfb6f154)
    at /usr/src/debug/system-server-0.1.65/ss_main.c:112
 #10 0x0804bdfe in main (argc=1, argv=0xbfb6f154)
    at /usr/src/debug/system-server-0.1.65/ss_main.c:119

Change-Id: If840b4ae2668deb6f585d85829bdb313ef65a18c
Signed-off-by: Chengwei Yang <chengwei.yang@intel.com>