Adapt to changes in Gerrit core

Change Iebfc5301a changed the ExceptionHook interface.

Change-Id: Ie62d8107db854c9bd91f25b263ba394cf7dafa2d
Signed-off-by: Edwin Kempin <ekempin@google.com>

java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersExceptionHook.java

diff --git a/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersExceptionHook.java b/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersExceptionHook.java
index 5eb316c..a965468 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersExceptionHook.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersExceptionHook.java
@@ -16,7 +16,7 @@
 
 import com.google.common.base.Throwables;
 import com.google.common.collect.ImmutableList;
-import com.google.gerrit.common.Nullable;
+import com.google.common.collect.ImmutableSet;
 import com.google.gerrit.plugins.codeowners.backend.config.CodeOwnersPluginConfiguration;
 import com.google.gerrit.plugins.codeowners.backend.config.InvalidPluginConfigurationException;
 import com.google.gerrit.plugins.codeowners.metrics.CodeOwnerMetrics;
@@ -56,7 +56,7 @@
   }
 
   @Override
-  public ImmutableList<String> getUserMessages(Throwable throwable, @Nullable String traceId) {
+  public ImmutableList<String> getUserMessages(Throwable throwable, ImmutableSet<String> traceId) {
     Optional<InvalidPluginConfigurationException> invalidPluginConfigurationException =
         getInvalidPluginConfigurationCause(throwable);
     if (invalidPluginConfigurationException.isPresent()) {