解决pycurl安装错误
由于libcurl的源码编译因素，在安装pycurl可能会导致以下两种错误。
错误1：
ImportError: pycurl: libcurl link-time ssl backend (openssl) is different from compile-time ssl backend (none/other)
错误1的解决办法如下：
$ pip uninstall pycurl
$ export PYCURL_SSL_LIBRARY=openssl$ pip install pycurl
错误2：
ImportError: pycurl: libcurl link-time ssl backend (nss)
is different from compile-time ssl backend (openssl)
错误2的解决办法如下：
$ pip uninstall pycurl
$ export PYCURL_SSL_LIBRARY=nss
$ pip install pycurl
参考
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