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>
Minor change to match naming convention in other collectors.
Initialize the proc or sys FS instance once while initializing
each collector instead of re-creating for each metric update.
Signed-off-by: Paul Gier <pgier@redhat.com>
