ggsn: Drop unneeded m_ggsn_supports_echo_interval

Latest osmo-ggsn release is 1.5.0, so this param is not needed at all.

Change-Id: Ie1c3cde2a01e8ea49aadcb1f7384995cb68039cb
diff --git a/ggsn_tests/GGSN_Tests.ttcn b/ggsn_tests/GGSN_Tests.ttcn
index 44dba4a..40506df 100644
--- a/ggsn_tests/GGSN_Tests.ttcn
+++ b/ggsn_tests/GGSN_Tests.ttcn
@@ -64,13 +64,6 @@
 		 * The tests expect to be able to send ping packets between any two simulated MS within the same
 		 * address range. This requires IP forwarding to be enabled on the corresponding tun interfaces.
 		 */
-
-		/*
-		 * Whether ggsn supports "(no) echo-interval" VTY command
-		 * (osmo-ggsn.git Id2c84165dc59dff495106758146a701ca488834f).
-		 * This option can be dropped after osmo-ggsn release > 1.4.0 exists.
-		 */
-		boolean m_ggsn_supports_echo_interval := true;
 	}
 
 	type set PdpContext {
@@ -203,9 +196,7 @@
 
 		f_init_vty();
 		f_vty_set_gpdu_txseq(use_gtpu_txseq);
-		if (m_ggsn_supports_echo_interval) {
-			f_vty_enable_echo_interval(g_use_echo);
-		}
+		f_vty_enable_echo_interval(g_use_echo);
 	}
 
 	/* Altstep implementing responses to any incoming echo requests */
@@ -1506,8 +1497,6 @@
 		execute(TC_pdp_act2_recovery());
 		execute(TC_act_deact_retrans_duplicate());
 
-		if (m_ggsn_supports_echo_interval) {
-			execute(TC_pdp_act_restart_ctr_echo());
-		}
+		execute(TC_pdp_act_restart_ctr_echo());
 	}
 }