Create a single backtrace library.

This library will be used to abstract away getting backtrace
data from how it is implemented. This is the first step to
replacing libcorkscrew with libunwind.

Bug: 8410085
Change-Id: Ie8f159e96a055d378e1ddc72d40239fba4cf52b7
Trigger a policy reload from post-fs-data.

Once userdata is available and decrypted, trigger a policy reload to pick
up any policy update files stored under /data/security.

Change-Id: Ic2b3121c3395429b108c40d1d7f5a3124a5896c5
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>