【摘要】操作系统：Ubuntu-16.04，pip安装module时两个报错：Cryptography_HAS_SSL_ST，openssl/opensslv.h: No such file的解决。

错误一提示：
File “build/bdist.linux-x86_64/egg/OpenSSL/__init__.py”, line 8, in
File “build/bdist.linux-x86_64/egg/OpenSSL/SSL.py”, line 194, in
AttributeError: ‘module’ object has no attribute ‘Cryptography_HAS_SSL_ST’

错误二提示：
creating /tmp/easy_install-EXVhCS/cryptography-2.4.2/.eggs/pycparser-2.19-py2.7.egg
Extracting pycparser-2.19-py2.7.egg to /tmp/easy_install-EXVhCS/cryptography-2.4.2/.eggs

Installed /tmp/easy_install-EXVhCS/cryptography-2.4.2/.eggs/pycparser-2.19-py2.7.egg
/usr/lib/python2.7/distutils/dist.py:267: UserWarning: Unknown distribution option: ‘python_requires’
warnings.warn(msg)
no previously-included directories found matching ‘docs/_build’
warning: no previously-included files matching ‘*’ found under directory ‘vectors’
build/temp.linux-x86_64-2.7/_openssl.c:498:30: fatal error: openssl/opensslv.h: No such file or directory
compilation terminated.
error: Setup script exited with error: command ‘x86_64-linux-gnu-gcc’ failed with exit status 1

还是缺少系统依赖导致，需要安装如下包：
apt-get install libffi-dev
apt-get install libssl-dev

python -m easy_install –upgrade pyOpenSSL
pip install -i https://pypi.tuna.tsinghua.edu.cn/simple pymysql