gprs_ns2: fix nsvc block and unblock vty command

e7dfeac8dcb3 introduced a regression in the block/unblock check
as it was using the priv->initiate_block instead of priv->om_blocked.
The initiate_block tracks who is responsible to unblock the NSVC.

Fixes: e7dfeac8dcb3 ("gprs_ns2_vty: print a response to vty `nsvc <nsvci> (block|unblock|reset)")
Change-Id: I516faea223e30b120a297faed10636daa554be8a
diff --git a/src/gb/gprs_ns2_vc_fsm.c b/src/gb/gprs_ns2_vc_fsm.c
index 9a6bfc2..7ed8299 100644
--- a/src/gb/gprs_ns2_vc_fsm.c
+++ b/src/gb/gprs_ns2_vc_fsm.c
@@ -785,7 +785,7 @@
 int ns2_vc_block(struct gprs_ns2_vc *nsvc)
 {
 	struct gprs_ns2_vc_priv *priv = nsvc->fi->priv;
-	if (priv->initiate_block)
+	if (priv->om_blocked)
 		return -EALREADY;
 
 	return osmo_fsm_inst_dispatch(nsvc->fi, GPRS_NS2_EV_REQ_OM_BLOCK, NULL);
@@ -797,7 +797,7 @@
 int ns2_vc_unblock(struct gprs_ns2_vc *nsvc)
 {
 	struct gprs_ns2_vc_priv *priv = nsvc->fi->priv;
-	if (!priv->initiate_block)
+	if (!priv->om_blocked)
 		return -EALREADY;
 
 	return osmo_fsm_inst_dispatch(nsvc->fi, GPRS_NS2_EV_REQ_OM_UNBLOCK, NULL);