Remove repoManager

Follows up https://gerrit-review.googlesource.com/#/c/91584/

Change-Id: I75fe549140537dd972ed22a8fb40506e61cf4064
diff --git a/src/main/java/com/googlesource/gerrit/plugins/branchnetwork/data/GitCommitCacheRefresh.java b/src/main/java/com/googlesource/gerrit/plugins/branchnetwork/data/GitCommitCacheRefresh.java
index 851cbcb..6ec6825 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/branchnetwork/data/GitCommitCacheRefresh.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/branchnetwork/data/GitCommitCacheRefresh.java
@@ -31,7 +31,6 @@
       @Named(GitCommitCache.GRAPH_DATA_CACHE) final LoadingCache<String,
       List<Commit>> networkGraphDataCache) {
     this.networkGraphDataCache = networkGraphDataCache;
-    this.repoManager = repoManager;
   }
 
   @Override