Named return variables should only be used to describe the returned type
further, e.g. `err error` doesn't add any new information and is just
stutter.
Remove all hardcoded references to `/proc`. For all collectors that do
not use `github.com/prometheus/procfs` yet, provide a wrapper to
generate the full paths.
Reformulate help strings, errors and comments to remove absolute
references to `/proc`.
This is a breaking change: the `-collector.ipvs.procfs` flag is removed
in favor of the general flag. Since it only affected that collector it
was only useful for development, so this should not cause many issues.
Tobias Schmidt
Julius Volz
Matthias Rampke
Jari Takkala
Siavash Safi