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/reporting/billing/BillingEmailUtils.java

@@ -20,7 +20,6 @@ import static java.nio.charset.StandardCharsets.UTF_8;
 import com.google.appengine.tools.cloudstorage.GcsFilename;
 import com.google.common.collect.ImmutableList;
 import com.google.common.io.CharStreams;
-import com.google.common.logging.FormattingLogger;
 import google.registry.config.RegistryConfig.Config;
 import google.registry.gcs.GcsUtils;
 import google.registry.reporting.billing.BillingModule.InvoiceDirectoryPrefix;
@@ -75,8 +74,6 @@ class BillingEmailUtils {
     this.retrier = retrier;
   }
 
-  private static final FormattingLogger logger = FormattingLogger.getLoggerForCallerClass();
-
   /** Sends an e-mail to all expected recipients with an attached overall invoice from GCS. */
   void emailOverallInvoice() {
     try {
@@ -114,13 +111,12 @@ class BillingEmailUtils {
           IOException.class,
           MessagingException.class);
     } catch (Throwable e) {
-      logger.severe(e, "Emailing invoice failed");
       // Strip one layer, because callWithRetry wraps in a RuntimeException
       sendAlertEmail(
           String.format(
               "Emailing invoice failed due to %s",
               getRootCause(e).getMessage()));
-      throw e;
+      throw new RuntimeException("Emailing invoice failed", e);
     }
   }
 
@@ -139,8 +135,7 @@ class BillingEmailUtils {
           },
           MessagingException.class);
     } catch (Throwable e) {
-      logger.severe(e, "The alert e-mail system failed.");
-      throw e;
+      throw new RuntimeException("The alert e-mail system failed.", e);
     }
   }
 }