Add PHOST to backend

[hebo1982]

the road of request : nginx-> nginx-ingress-> tomcat. If use https, the first nginx use 443 port . the next nginx-ingress and tomcat use 80
port.

so nginx-ingress use "PHOST" to show the real host for backends. Removes
https support from nginx-ingress.

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[k8s-reviewable]

This change is 

[aledbf]

You can achieve this using a custom template.

[aledbf]

Please close this PR. We cannot remove the https feature

[coveralls]

Coverage remained the same at 44.543% when pulling 0badc6c on ananas-hebo:master into 0aa41ec on kubernetes:master.