Remove unnecessary quotes around git_private_key
Remove unnecessary quotes around git_private_key

- in azure install-pcf pipeline

[#150900818] pivotal-cf/pcf-pipelines #181: [Azure] Empty `trusted_certificates` param causes `config-director.sh` to fail

pivotal-cf/pcf-pipelines,BrianMMcClain/pcf-pipelines,pivotal-cf/pcf-pipelines,sandyg1/pcf-pipelines,cah-josephgeorge/pcf-pipelines,BrianMMcClain/pcf-pipelines,cah-josephgeorge/pcf-pipelines,sandyg1/pcf-pipelines,pvsone/pcf-pipelines,rahulkj/pcf-pipelines,pivotal-cf/pcf-pipelines,pvsone/pcf-pipelines,rahulkj/pcf-pipelines,pvsone/pcf-pipelines,sandyg1/pcf-pipelines,rahulkj/pcf-pipelines,pivotal-cf/pcf-pipelines,mcb/pcf-pipelines,rahulkj/pcf-pipelines,mcb/pcf-pipelines,mcb/pcf-pipelines,sandyg1/pcf-pipelines,cah-josephgeorge/pcf-pipelines