Add a new pattern to allow moving the flag handling out of the collector
package and into a separate package. This allows collector package users
to create their own config or flag handling.
Signed-off-by: Ben Kochie <superq@gmail.com>
Fix the error logging of the promhttp handler by connecting it to the
promlog setup.
* Switch to go-kit/log.
* Cleanup CHANGELOG.
Fixes: https://github.com/prometheus/node_exporter/issues/1886
Signed-off-by: Ben Kochie <superq@gmail.com>
