批量升级 python 库遇到的问题及解决办法
批量升级 python 库需要用到 pip-review，先安装一下：
pip install pip-review
然后开始批量升级 python 库：
pip-review --interactive
不料遇到报错：
xattr.c:29:24: fatal error: attr/xattr.h: No such file or directory
解决一下：
sudo yum install -y libattr-devel
另外，尝试运行
yum install python-devel
结果，升级 pycurl 遇到问题：
There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:
pycurl: libcurl link-time ssl backend (nss) is different from compile-time ssl backend (none/other)
Please install a package which provides this module, or
verify that the module is installed correctly.
It's possible that the above module doesn't match the
current version of Python, which is:
2.7.5 (default, Aug 4 2017, 00:39:18)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-16)]
解决方法如下：
pip uninstall pycurl
export PYCURL_SSL_LIBRARY=nss
easy_install pycurl
最后，再次尝试升级
pip-review --interactive
成功。
不过，还有一点提醒：
DEPRECATION: Uninstalling a distutils installed project (urlgrabber) has been deprecated and will be removed in a future version. This is due to the fact that uninstalling a distutils project will only partially uninstall the project.
卸载 distutils 安装的 python 模块，只能部分卸载，也就是删不干净，所以这种卸载方法已标记为不推荐使用，并且将在未来的版本中彻底废弃。请勿依赖这种卸载方法。