Migrate to internal FormattingLogger in preparation of migration to Flogger

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=197744904

java/google/registry/security/BUILD

@@ -11,6 +11,7 @@ java_library(
         exclude = glob(["*Servlet.java"]),
     ),
     deps = [
+        "//java/com/google/common/logging:formatting_logger",
         "//java/google/registry/model",
         "//java/google/registry/util",
         "//third_party/objectify:objectify-v4_1",

java/google/registry/security/JsonHttp.java

@@ -20,8 +20,8 @@ import static com.google.common.net.HttpHeaders.X_CONTENT_TYPE_OPTIONS;
 import static com.google.common.net.MediaType.JSON_UTF_8;
 import static org.json.simple.JSONValue.writeJSONString;
 
+import com.google.common.logging.FormattingLogger;
 import com.google.common.net.MediaType;
-import google.registry.util.FormattingLogger;
 import java.io.IOException;
 import java.io.Reader;
 import java.io.Writer;

java/google/registry/security/XsrfTokenManager.java

@@ -23,9 +23,9 @@ import com.google.appengine.api.users.UserService;
 import com.google.common.base.Joiner;
 import com.google.common.base.Splitter;
 import com.google.common.hash.Hashing;
+import com.google.common.logging.FormattingLogger;
 import google.registry.model.server.ServerSecret;
 import google.registry.util.Clock;
-import google.registry.util.FormattingLogger;
 import java.util.List;
 import javax.inject.Inject;
 import org.joda.time.DateTime;