python3.7安装， 解决pip is configured with locations that require TLS/SSL问题

1、错误信息
pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.

2 、原因
系统版本centos6.5，其中openssl的版本为OpenSSL 1.0.1e-fips 11 Feb 2013,而python3.7需要的openssl的版本为1.0.2或者1.1.x,需要对openssl进行升级，并重新编译python3.7.0。yum 安装的openssl 版本都比较低。

2.1 升级openssl
# 1.下贼openssl
wget https://www.openssl.org/source/openssl-1.1.1a.tar.gz
tar -zxvf openssl-1.1.1a.tar.gz
cd openssl-1.1.1a
# 2.编译安装
./config --prefix=/usr/local/openssl no-zlib #不需要zlib
make
make install
# 3.备份原配置
mv /usr/bin/openssl /usr/bin/openssl.bak
mv /usr/include/openssl/ /usr/include/openssl.bak
# 4.新版配置
ln -s /usr/local/openssl/include/openssl /usr/include/openssl
ln -s /usr/local/openssl/lib/libssl.so.1.1 /usr/local/lib64/libssl.so
ln -s /usr/local/openssl/bin/openssl /usr/bin/openssl
# 5.修改系统配置
## 写入openssl库文件的搜索路径
echo "/usr/local/openssl/lib" >> /etc/ld.so.conf
## 使修改后的/etc/ld.so.conf生效 
ldconfig -v
# 6.查看openssl版本
openssl version

openssl version 提示：

 /usr/local/openssl/bin/openssl: error while loading shared libraries: libssl.so.1.1: cannot open shared object file: No such file or directory

假如你的libssl.so.1.1 文件在/usr/local/openssl/lib/下面，可以这样做

ln -s /usr/local/openssl/lib/libssl.so.1.1 /usr/lib64/libssl.so.1.1

ln -s /usr/local/openssl/lib/libcrypto.so.1.1 /usr/lib64/libcrypto.so.1.1

3、 重新安装python
./configure --prefix=/usr/local/python3 --with-openssl=/usr/local/openssl
make
make install