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

This reverts commit 1d8b5d25 which is
commit aa5762c3 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