Implement 'Restore Change' feature.

Now it is possible to restore status of abandoned changes to 'NEW'.
It helps in a situation when a change has been abandoned accidently.

Bug: issue 312
Change-Id: Iba61dcf82a9b5ee5b78cd529b041f92a042a9611

gerrit-common/src/main/java/com/google/gerrit/common/data/ChangeDetail.java

@@ -30,6 +30,7 @@ public class ChangeDetail {
   protected AccountInfoCache accounts;
   protected boolean allowsAnonymous;
   protected boolean canAbandon;
+  protected boolean canRestore;
   protected Change change;
   protected boolean starred;
   protected List<ChangeInfo> dependsOn;
@@ -69,6 +70,14 @@ public class ChangeDetail {
     canAbandon = a;
   }
 
+  public boolean canRestore() {
+    return canRestore;
+  }
+
+  public void setCanRestore(final boolean a) {
+    canRestore = a;
+  }
+
   public Change getChange() {
     return change;
   }