Remove /api/v1/delete_series docs for 2.0 (#3425)
Remove /api/v1/delete_series docs for 2.0 (#3425)

This endpoint has moved to /api/v2 (with somewhat different properties)
in Prometheus 2.0 and should now be part of a separate admin API page.
kangwoo/prometheus,Gouthamve/prometheus,brancz/prometheus,keegancsmith/prometheus,amorken/prometheus,AlekSi/prometheus,GoogleCloudPlatform/prometheus,Stackdriver/stackdriver-prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,prometheus/prometheus,keegancsmith/prometheus,prometheus/prometheus,keegancsmith/prometheus,kangwoo/prometheus,Gouthamve/prometheus,prometheus/prometheus,Stackdriver/stackdriver-prometheus,Stackdriver/stackdriver-prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,brancz/prometheus,Conorbro/prometheus,alileza/prometheus,prometheus/prometheus,brancz/prometheus,alileza/prometheus,GoogleCloudPlatform/prometheus,Conorbro/prometheus,amorken/prometheus,keegancsmith/prometheus,AlekSi/prometheus,kangwoo/prometheus,Conorbro/prometheus,alileza/prometheus,Stackdriver/stackdriver-prometheus,amorken/prometheus,brancz/prometheus,kangwoo/prometheus,AlekSi/prometheus,keegancsmith/prometheus,Gouthamve/prometheus,amorken/prometheus,Gouthamve/prometheus,Conorbro/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,AlekSi/prometheus