Migrate to Flogger (green)

This is a 'green' Flogger migration CL. Green CLs are intended to be as
safe as possible and should be easy to review and submit.

No changes should be necessary to the code itself prior to submission,
but small changes to BUILD files may be required.

Changes within files are completely independent of each other, so this CL
can be safely split up for review using tools such as Rosie.

For more information, see []
Base CL: 197826149

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=198560170

java/google/registry/dns/writer/VoidDnsWriter.java

@@ -14,7 +14,7 @@
 
 package google.registry.dns.writer;
 
-import com.google.common.logging.FormattingLogger;
+import com.google.common.flogger.FluentLogger;
 import java.util.HashSet;
 import java.util.Set;
 import javax.inject.Inject;
@@ -32,7 +32,7 @@ public final class VoidDnsWriter extends BaseDnsWriter {
    */
   public static final String NAME = "VoidDnsWriter";
 
-  private static final FormattingLogger logger = FormattingLogger.getLoggerForCallerClass();
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
   private final Set<String> names = new HashSet<>();
 
@@ -51,7 +51,7 @@ public final class VoidDnsWriter extends BaseDnsWriter {
 
   @Override
   protected void commitUnchecked() {
-    logger.warningfmt(
+    logger.atWarning().log(
         "No DnsWriterFactory implementation specified; ignoring names to commit: %s", names);
   }
 }