fix centos git certificate error

Fix the git error on CentOS

The error is related to corp certificate.

1. sudo yum install -y ca-certificates
2. download the emc certificates from: https://eos2git.cec.lab.emc.com/liangr/corp-notes/blob/master/emc_cert/emc_cacert.crt
3. cp emc_cacert.crt /etc/pki/ca-trust/source/anchors/
4. run command: update-ca-trust extract