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/gcs/BUILD

@@ -8,8 +8,8 @@ java_library(
     name = "gcs",
     srcs = glob(["*.java"]),
     deps = [
+        "//java/com/google/common/logging:formatting_logger",
         "//java/google/registry/config",
-        "//java/google/registry/util",
         "@com_google_appengine_tools_appengine_gcs_client",
         "@com_google_code_findbugs_jsr305",
         "@com_google_dagger",

java/google/registry/gcs/GcsUtils.java

@@ -26,9 +26,9 @@ import com.google.appengine.tools.cloudstorage.ListResult;
 import com.google.common.base.Splitter;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.logging.FormattingLogger;
 import com.google.common.net.MediaType;
 import google.registry.config.RegistryConfig.Config;
-import google.registry.util.FormattingLogger;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;