Adapt to ProjectCache#get interface change

Change-Id: Ic6a03ffd5a45cee95da58963a3178f5150bcf00c
diff --git a/src/main/java/com/googlesource/gerrit/plugins/deleteproject/HideProject.java b/src/main/java/com/googlesource/gerrit/plugins/deleteproject/HideProject.java
index c5bf8ce..7656726 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/deleteproject/HideProject.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/deleteproject/HideProject.java
@@ -84,7 +84,7 @@
   }
 
   private void createProjectIfMissing(String projectName) throws IOException, RestApiException {
-    if (projectCache.get(Project.nameKey(projectName)) == null) {
+    if (!projectCache.get(Project.nameKey(projectName)).isPresent()) {
       try {
         createProject.apply(TopLevelResource.INSTANCE, IdString.fromDecoded(projectName), null);
       } catch (RestApiException | ConfigInvalidException | PermissionBackendException e) {