Update changelog, improve warning message from last commit.

ChangeLog.txt

@@ -4,6 +4,9 @@
 Broker:
 - Fix detection of incoming v3.1/v3.1.1 bridges. Closes #1263.
 
+Clients:
+- Fix -L url parsing when `/topic` part is missing.
+
 
 1.6.2 - 20190430
 ================

client/client_shared.c

@@ -663,7 +663,7 @@ int client_config_line_proc(struct mosq_config *cfg, int pub_or_sub, int argc, c
 				}
 				topic = strchr(url, '/');
 				if(!topic){
-					fprintf(stderr, "Error: invalid URL for -L argument specified.\n\n");
+					fprintf(stderr, "Error: Invalid URL for -L argument specified - topic missing.\n");
 					return 1;
 				}
 				*topic++ = 0;