Fixes initialization bug in USAP pool properties.

This patch fixes an initialization order bug in the USAP pool policy
management code.  Previously, bad values were used when initializing the
USAP pool when it was enabled on device boot.  This patch ensures that
the policy system properties have been checked before the pool is
initialized.

Test: Boot with USAP pool enabled
Change-Id: I29d91abd511bc35c7a70a3a56668c7ee2290864b