DNP: avoid a divide-by-zero error if we encounter unknown media.

backend_dnpds40.c

@@ -714,7 +714,7 @@ static void dnpds40_attach(void *vctx, struct libusb_device_handle *dev,
 				ctx->media_count_new = 180;
 				break;
 			default:
-				ctx->media_count_new = 0;
+				ctx->media_count_new = 999; // non-zero
 			}
 			break;
 		case P_DNP_DSRX1:
@@ -726,7 +726,7 @@ static void dnpds40_attach(void *vctx, struct libusb_device_handle *dev,
 				ctx->media_count_new = 350;
 				break;
 			default:
-				ctx->media_count_new = 0;
+				ctx->media_count_new = 999; // non-zero
 			}
 			break;
 		case P_DNP_DS80:
@@ -739,11 +739,11 @@ static void dnpds40_attach(void *vctx, struct libusb_device_handle *dev,
 				ctx->media_count_new = 110;
 				break;
 			default:
-				ctx->media_count_new = 0;
+				ctx->media_count_new = 999; // non-zero
 			}
 			break;
 		default:
-			ctx->media_count_new = 0;
+			ctx->media_count_new = 999; // non-zero
 			break;
 		}
 	}
@@ -2211,7 +2211,7 @@ static int dnpds40_cmdline_arg(void *vctx, int argc, char **argv)
 /* Exported */
 struct dyesub_backend dnpds40_backend = {
 	.name = "DNP DS40/DS80/DSRX1/DS620",
-	.version = "0.87",
+	.version = "0.88",
 	.uri_prefix = "dnpds40",
 	.cmdline_usage = dnpds40_cmdline,
 	.cmdline_arg = dnpds40_cmdline_arg,