Documentation/op-guide: Remove HTTP alerts
Documentation/op-guide: Remove HTTP alerts

The HTTP metrics have been deprecated and removed. In other places all
the HTTP related alerts have already been removed, this is just a clean
up of the remaining places these were left.

gyuho/etcd,etcd-io/etcd,vimalk78/etcd,etcd-io/etcd,sinsharat/etcd,dannysauer/etcd,cockroachdb/etcd,ajityagaty/etcd,dannysauer/etcd,mkumatag/etcd,cockroachdb/etcd,mqliang/etcd,rnaveiras/etcd,mqliang/etcd,li-ang/etcd,ajityagaty/etcd,joshix/etcd,gyuho/etcd,mqliang/etcd,mkumatag/etcd,li-ang/etcd,ajityagaty/etcd,rnaveiras/etcd,xiang90/etcd,coreos/etcd,etcd-io/etcd,vimalk78/etcd,rnaveiras/etcd,coreos/etcd,mkumatag/etcd,sinsharat/etcd,xiang90/etcd,joshix/etcd