Previously the `__address__` label could contain only `host:port` part of the target url,
while the scheme and metrics path were obtained from `__scheme__` and `__metrics_path__`
labels. Now it is possible to set the full url in `__address__` label.
This makes valid the following scrape config, which is frequently used by novice users:
scrape_configs:
- job_name: foo
static_configs:
- targets:
- http://host1/metrics1
- https://host2/metrics2
