rtpengine: aliased rtpengine_destroy() to rtpengine_delete()

- make it easier to migrate from rtp proxy by replacing the module name
  inside routing blocks

src/modules/rtpengine/rtpengine.c

@@ -514,6 +514,11 @@ static cmd_export_t cmds[] = {
 		fixup_spve_null, fixup_free_spve_null, ANY_ROUTE},
 	{"rtpengine_delete", (cmd_function)rtpengine_delete1_f, 2,
 		fixup_spve_spve, fixup_free_spve_spve, ANY_ROUTE},
+	{"rtpengine_destroy", (cmd_function)rtpengine_delete1_f, 0, 0, 0, ANY_ROUTE},
+	{"rtpengine_destroy", (cmd_function)rtpengine_delete1_f, 1,
+		fixup_spve_null, fixup_free_spve_null, ANY_ROUTE},
+	{"rtpengine_destroy", (cmd_function)rtpengine_delete1_f, 2,
+		fixup_spve_spve, fixup_free_spve_spve, ANY_ROUTE},
 	{"rtpengine_query", (cmd_function)rtpengine_query1_f, 0, 0, 0, ANY_ROUTE},
 	{"rtpengine_query", (cmd_function)rtpengine_query1_f, 1,
 		fixup_spve_null, fixup_free_spve_null, ANY_ROUTE},