audio policy: engine configurable: support fail safe

When the parameter manager could not be launched, the engine will abort if
LOG_NDEBUG is defined, unless a segmentation fault will happen later.
This patch allows fail safe feature when LOG_NDEBUG is not defined.

Change-Id: Ie78575bddad6d19beed61673979e1b8ef1c70b0e
Signed-off-by: François Gaffie <francois.gaffie@intel.com>