Add attestation to group pkcs11

Attestation daemon uses chaps for pkcs11 key store. Chaps daemon
accepts dbus messages only from group pkcs11.

CQ-DEPEND=CL:376038
BUG=chrome-os-partner:54712
BUG=chrome-os-partner:54710
TEST=on tpm2 board, run "attestation_client info --user=zzz", check log
     for "Chaps service is not available: Rejected send message" messages.

Change-Id: I79900c7656a2c9440d460c3eb1d6137947f77135
Reviewed-on: https://chromium-review.googlesource.com/375478
Commit-Ready: Andrey Pronin <apronin@chromium.org>
Tested-by: Andrey Pronin <apronin@chromium.org>
Reviewed-by: Darren Krahn <dkrahn@chromium.org>
diff --git a/profiles/base/accounts/group/pkcs11 b/profiles/base/accounts/group/pkcs11
index 9f99e95..54e0a70 100644
--- a/profiles/base/accounts/group/pkcs11
+++ b/profiles/base/accounts/group/pkcs11
@@ -1,4 +1,4 @@
 group:pkcs11
 gid:208
 # These users all need access to PKCS #11 crypto services.
-users:root,ipsec,chronos,chaps,wpa
+users:root,ipsec,chronos,chaps,wpa,attestation