exit a loop if read() returns 0 because socket might be closed

related to http://hipbyte.myjetbrains.com/youtrack/issue/RM-309

This will fix a freeze when terminate lldb with "quit" command

bin/deploy.m

@@ -898,12 +898,18 @@ start_debug_server(am_device_t dev)
 		    if (len > 0) {
 			write(gdb_fd, buf, len);
 		    }
+		    else {
+			break;
+		    }
 		}
 		if (FD_ISSET(gdb_fd, &read_fds)) {
 		    len = read(gdb_fd, buf, sizeof buf);
 		    if (len > 0) {
 			write(lldb_socket, buf, len);
 		    }
+		    else {
+			break;
+		    }
 		}
 	    }
 	}