Remove unused logger instance

Change-Id: Icdf4293f246654874bd6f5a0cb79aac14814e2f1
diff --git a/java/com/google/gerrit/server/permissions/DefaultRefFilter.java b/java/com/google/gerrit/server/permissions/DefaultRefFilter.java
index 9a7bb18..56c22e1 100644
--- a/java/com/google/gerrit/server/permissions/DefaultRefFilter.java
+++ b/java/com/google/gerrit/server/permissions/DefaultRefFilter.java
@@ -22,7 +22,6 @@
 import static java.util.stream.Collectors.toMap;
 
 import com.google.common.collect.ImmutableSet;
-import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.metrics.Counter0;
@@ -63,8 +62,6 @@
 import org.eclipse.jgit.lib.SymbolicRef;
 
 class DefaultRefFilter {
-  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
-
   interface Factory {
     DefaultRefFilter create(ProjectControl projectControl);
   }