[Bluetooth] Bugfix: prevent memory leak

[Bluetooth] Bugfix: prevent memory leak

In the previous implementation if a service was successfully created,
but its registration failed, the resources associated with its handle
were not released.
Such a situation has occurred when Bluetooth was disabled and
BluetoothGATTServer::registerService() was called.
This commit adds the missing line that destroys the handle.

[Verification] The code compiles.
Tested in chrome console - server is successfully created and reports
errors in case of disabled bluetooth adapter. No crash or other issues observed.

Change-Id: I85741e51638abd6b5443d7f7ce5d84e9279fc498
Signed-off-by: Pawel Wasowski <p.wasowski2@samsung.com>