From: Lucian Adrian Grijincu <redacted>
Date: Wed, 12 Jan 2011 12:19:10 +0200
The IPV4_DEVCONF_* enums are never exposed to the userspace and it
would make code simpler to remove all the useless (-1) adjustments.
Starting values like this at "1" is usually done on purpose.
It allows "0" to be illegal or mean "none", and thus easily trapping
cases where the value fails to be initialized properly. In this way
the illegal sentinel "0" doesn't take up any space either.