ChangesByProjectCacheImpl: Remove unused import

Not sure why this wasn't caught by gjf earlier.

Change-Id: I9b1306f51e6218364e8ae9f43274e12b520d4797
Release-Notes: skip

java/com/google/gerrit/server/git/ChangesByProjectCacheImpl.java

diff --git a/java/com/google/gerrit/server/git/ChangesByProjectCacheImpl.java b/java/com/google/gerrit/server/git/ChangesByProjectCacheImpl.java
index f954b81..7f9b245 100644
--- a/java/com/google/gerrit/server/git/ChangesByProjectCacheImpl.java
+++ b/java/com/google/gerrit/server/git/ChangesByProjectCacheImpl.java
@@ -24,7 +24,6 @@
 import com.google.gerrit.entities.Project;
 import com.google.gerrit.server.ReviewerSet;
 import com.google.gerrit.server.cache.CacheModule;
-import com.google.gerrit.server.git.ChangesByProjectCache.UseIndex;
 import com.google.gerrit.server.index.change.ChangeField;
 import com.google.gerrit.server.logging.Metadata;
 import com.google.gerrit.server.logging.TraceContext;