Revert "netfilter: conntrack: NF_CONNTRACK_PROCFS should no longer default to y"

This reverts commit 63c79058 which is
commit aa5762c34213aba7a72dc58e70601370805fa794 upstream.

It changes the default configuration options, which breaks the Android
kernel abi, which is not a good thing at the moment.  So revert this for
now as it's not needed for this Android branch.

Bug: 161946584
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ia6bcc02c5f1e3e527f69f859a7e0deccc9d546dd