Fixed:

1. When mysql_config not installed
2. When virtualenv not installed
3. Bugfix: Setup database Access denied

使用 setup_databases.sh确实更块的设置mysql,但是使用command|mysql 这样的方式本身有问题,因为没有指定账号密码,比如我这里报错:

```
Setup database...
ERROR 1044 (42000) at line 1: Access denied for user ''@'localhost' to database 'valentine'
ERROR 1044 (42000) at line 1: Access denied for user ''@'localhost' to database 'valentine'
```

我设计了一个提示输入账号密码的一步