fix error messages

src/core/surface/channel.c

@@ -113,7 +113,7 @@ grpc_channel *grpc_channel_create_from_filters(
         }
       } else if (0 == strcmp(args->args[i].key, GRPC_ARG_DEFAULT_AUTHORITY)) {
         if (args->args[i].type != GRPC_ARG_STRING) {
-          gpr_log(GPR_ERROR, "%s: must be an string",
+          gpr_log(GPR_ERROR, "%s ignored: it must be a string",
                   GRPC_ARG_DEFAULT_AUTHORITY);
         } else {
           if (channel->default_authority) {
@@ -126,12 +126,12 @@ grpc_channel *grpc_channel_create_from_filters(
       } else if (0 ==
                  strcmp(args->args[i].key, GRPC_SSL_TARGET_NAME_OVERRIDE_ARG)) {
         if (args->args[i].type != GRPC_ARG_STRING) {
-          gpr_log(GPR_ERROR, "%s: must be an string",
+          gpr_log(GPR_ERROR, "%s ignored: it must be a string",
                   GRPC_SSL_TARGET_NAME_OVERRIDE_ARG);
         } else {
           if (channel->default_authority) {
             /* other ways of setting this (notably ssl) take precedence */
-            gpr_log(GPR_ERROR, "%s: default host already set some other way",
+            gpr_log(GPR_ERROR, "%s ignored: default host already set some other way",
                     GRPC_ARG_DEFAULT_AUTHORITY);
           } else {
             channel->default_authority = grpc_mdelem_from_strings(