Rename OUT_OF_KEYS -> OUT_OF_KEYS_TRANSIENT

More OUT_OF_KEYS errors are coming, and the old "OUT_OF_KEYS" is a
bucket for all transient errors. Rename the enum to better indicate
this.

Also rename OUT_OF_KEYS_REQUIRES_UPGRADE to
OUT_OF_KEYS_REQUIRES_SECURITY_PATCH. This better indicates that
system is potentially vulnerable (rather than simply running old code).

Test: keystore2_test
Change-Id: I1f2d803529c3e43592536016a9261e2294b42bb5
diff --git a/keystore2/src/error.rs b/keystore2/src/error.rs
index b60b64f..d1d58a4 100644
--- a/keystore2/src/error.rs
+++ b/keystore2/src/error.rs
@@ -72,9 +72,9 @@
         Error::Rc(ResponseCode::PERMISSION_DENIED)
     }
 
-    /// Short hand for `Error::Rc(ResponseCode::OUT_OF_KEYS)`
+    /// Short hand for `Error::Rc(ResponseCode::OUT_OF_KEYS_TRANSIENT_ERROR)`
     pub fn out_of_keys() -> Self {
-        Error::Rc(ResponseCode::OUT_OF_KEYS)
+        Error::Rc(ResponseCode::OUT_OF_KEYS_TRANSIENT_ERROR)
     }
 }