Merge branch 'docs-Fix-failover-build-warnings'

Merge branch 'docs-Fix-failover-build-warnings'

Tobin C. Harding says:

====================
docs: Fix failover build warnings

This is my first patch set to net-next.  Please shout loud and clear if
I've botched anything.

Recently failover and net_failover modules were added to the mainline.
Documentation was included in rst format but they were not added to the
toctree in `networking/index.rst`.  Also building docs for net_failover
is currently emitting a few warnings.

Patch 1 adds failover and net_failover to the index toctree
Patch 2 fixes the build warnings for net_failover

I haven't been super active on netdev list so if there is some reason I
missed why these files are not in the index please do say so.

Has there been any discussion on preferred order for the toctree index
list?  I just added them to the bottom of the list.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>