Fix issue #729: xcat do not print message under heavy load scenario

The root cause of this issue is the select time out when polling the
pipe socket. When timeout occurs, child process exit before printing
the message at the parent process side.

close-issue: #729

xCAT-server/sbin/xcatd

@@ -1897,6 +1897,12 @@ sub plugin_command {
             $xcatresponses{xcatresponse}=[];
         }
     }
+    if ($check_fds->count > 0) {
+        my %resp_timeout = ('errorcode'=>[1],
+                            'data'=>["Warning: Process terminated due to IO timeout, the following output may not complete.\n"]);
+        push @{$xcatresponses{xcatresponse}},\%resp_timeout;
+        relay_fds($check_fds,$xcatresponses{xcatresponse});
+    }
     if (scalar(@{$xcatresponses{xcatresponse}})) {
         send_response(\%xcatresponses,$sock);
         $xcatresponses{xcatresponse}=[];