remove useless memset and \n

fgets reads up to one byte less than size then with \0 at the end
adding \n after \0 is useless too

Change-Id: I7758d7a8f885bdde2b491a9cb75800f831d77c1f

gui/action.cpp

@@ -1366,7 +1366,6 @@ int GUIAction::terminalcommand(std::string arg)
 					keep_going = 0;
 				} else {
 					// Try to read output
-					memset(line, 0, sizeof(line));
 					if(fgets(line, sizeof(line), fp) != NULL)
 						gui_print("%s", line); // Display output
 					else

twrp-functions.cpp

@@ -64,10 +64,7 @@ int TWFunc::Exec_Cmd(const string& cmd, string &result) {
 	exec = __popen(cmd.c_str(), "r");
 	if (!exec) return -1;
 	while(!feof(exec)) {
-		memset(&buffer, 0, sizeof(buffer));
 		if (fgets(buffer, 128, exec) != NULL) {
-			buffer[128] = '\n';
-			buffer[129] = 0;
 			result += buffer;
 		}
 	}