Enable secure mode in default configuration

Enable secure mode in default configuration

Enable secure mode in the default configuration file since the rest
of the default configuration is essentially set up to point at an
instance of the databroker set up by us, and thus running in secure
mode.  This makes the configuration more usable out of the box with
our typical full demo setups.

Bug-AGL: SPEC-5138

Change-Id: I99ad71de9e896c429874a0a13b76fd8bc269c90b
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
(cherry picked from commit 262fd5529462617cbb65747585498c8977cdd9db)