Handle error when accessing a closed socket handle.
Sylvain Fonteneau authored
When an application tries to access a closed socket, the NFC
service will fail to find it in its internal socket table,
returning a null object which is impossible to cast to a
LLCP socket class, generating a ClassCastException.

This patch handle the exception catching, avoiding a service
crash.

Change-Id: I236652b83a51b78fcfe8258402888a74f3144a7f
f5d6f325