Reuse ProjectInfo from ProjectJson in ListProjects

It doesn't make sense to have two ProjectInfo classes that are
virtually the same.

Change-Id: I7473b4227ec7ca0981722c4d6e88a7206b6e7aff
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>

gerrit-server/src/main/java/com/google/gerrit/server/project/ProjectJson.java

@@ -20,6 +20,8 @@ import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.config.AllProjectsName;
 import com.google.inject.Inject;
 
+import java.util.Map;
+
 public class ProjectJson {
 
   private final AllProjectsName allProjects;
@@ -49,6 +51,7 @@ public class ProjectJson {
     String name;
     String parent;
     String description;
+    Map<String, String> branches;
 
     void finish() {
       id = Url.encode(name);