Comment out unused parameter.

BUG: 17281763
Change-Id: I1881e31893cd2d84389e4b29a4408d58654c20ca
diff --git a/keystore/keystore.cpp b/keystore/keystore.cpp
index bda6948..27ced71 100644
--- a/keystore/keystore.cpp
+++ b/keystore/keystore.cpp
@@ -225,7 +225,7 @@
     return uid / AID_USER;
 }
 
-static bool keystore_selinux_check_access(uid_t uid, perm_t perm, pid_t spid) {
+static bool keystore_selinux_check_access(uid_t /*uid*/, perm_t perm, pid_t spid) {
     if (!ks_is_selinux_enabled) {
         return true;
     }