misc::docsite: Remove file "doc/index.html".

Puppet is currently conflicting this one file with the rest
of the docroot of the documentation site in integration/docroot.git

This resolves the conflict.

Change-Id: I5b5282c26c76a8d51e5f07ea91c4e4b9fe9279df
Merge "misc::docsite: Remove file "doc/index.html"." into production