staging/lustre: don't assert ln_refcount in LNetGetId

If LNetNIInit() fails, we'll get zero ln_refcount. So fail
LNetGetId() properly instead of asserting.

We can get to it when socklnd fails to scan network interfaces,
which is possible if Lustre is builtin.
Signed-off-by: NPeng Tao <tao.peng@emc.com>
Signed-off-by: NAndreas Dilger <andreas.dilger@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lnet/lnet/api-ni.c

@@ -1541,7 +1541,10 @@ LNetGetId(unsigned int index, lnet_process_id_t *id)
 	int		rc = -ENOENT;
 
 	LASSERT(the_lnet.ln_init);
-	LASSERT(the_lnet.ln_refcount > 0);
+
+	/* LNetNI initilization failed? */
+	if (the_lnet.ln_refcount == 0)
+		return rc;
 
 	cpt = lnet_net_lock_current();