credstore: Don't require credentials to use ACP ids starting at 0.

This fixes a bug in credstore where it only worked if a credential
used ACP ids starting at zero and upwards (e.g. no holes). This is not
a reasonable requirement, it just happened to be a bug which wasn't
triggered because all CTS tests uses identifiers starting at 0 with
no holes.

This bug-fix is merged along with a new CTS test to check this bug no
longer exists.

Bug: 160966911
Test: atest android.security.identity.cts
Test: New CTS test testProvisionAcpIdNotStartingAtZero
Merged-In: I58595e6bf5f3ca3f82ebe9291fde54b7cf11e0dd
Change-Id: I7731f24510a3d380c473906d5e771422bcb7efe7
1 file changed