gprs_ns2: when calling nsvc_force_unconf for a dynamic NSE drop the NSE.

The vty command is used for test cases to reset NSE state.
So dynamic NSE shouldn't present.

Related: SYS#5208
Change-Id: I0a4f35c974c8c3b79c48f2f56170722c95254332
diff --git a/src/gb/gprs_ns2_vty2.c b/src/gb/gprs_ns2_vty2.c
index 41daa74..5af8fbc 100644
--- a/src/gb/gprs_ns2_vty2.c
+++ b/src/gb/gprs_ns2_vty2.c
@@ -1491,7 +1491,9 @@
 		return CMD_WARNING;
 	}
 
-	if (nse->dialect == NS2_DIALECT_SNS) {
+	if (!nse->persistent) {
+		gprs_ns2_free_nse(nse);
+	} else if (nse->dialect == NS2_DIALECT_SNS) {
 		gprs_ns2_free_nsvcs(nse);
 	} else {
 		/* Perform the operation for all nsvc */