Keystore 2.0: Add keystore2 to llkd ignore list.

Due to Keystore's handling of sensitive information we cannot allow
any other process ptrace privileges over Keystore. To silence SELinux
denials llkd must ignore the keystore process.

This CL adds keystore2 to the ignore list because it replaces keystore.
In a followup the keystore entry will be removed.

Bug: 170144267
Test: N/A
Change-Id: I28eafc1f4341cdd371ad78d3a7a9ba8ac128c1b1