Check for a revision before request

When using the inline edit feature to add a depens-on element to the
commit message the revision may not be available for the REST
request.  Check to make sure it's available before showing getting
the data.

src/main/java/com/googlesource/gerrit/plugins/chound/client/LabelPanel.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/chound/client/LabelPanel.java b/src/main/java/com/googlesource/gerrit/plugins/chound/client/LabelPanel.java
index c12ceb8..5a49614 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/chound/client/LabelPanel.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/chound/client/LabelPanel.java
@@ -42,21 +42,23 @@
     final RevisionInfo rev =
         panel.getObject(GerritUiExtensionPoint.Key.REVISION_INFO).cast();
 
-    new RestApi("changes").id(change.id()).view("revisions").id(rev.id())
-        .view(Plugin.get().getPluginName(), "dependency")
-        .get(new AsyncCallback<DependencyInfo>() {
-          @Override
-          public void onSuccess(DependencyInfo result) {
-            if (result != null) {
-              display(result);
+    if (!rev.isEdit()) {
+      new RestApi("changes").id(change.id()).view("revisions").id(rev.id())
+          .view(Plugin.get().getPluginName(), "dependency")
+          .get(new AsyncCallback<DependencyInfo>() {
+            @Override
+            public void onSuccess(DependencyInfo result) {
+              if (result != null) {
+                display(result);
+              }
             }
-          }
 
-          @Override
-          public void onFailure(Throwable caught) {
-            // never invoked
-          }
-        });
+            @Override
+            public void onFailure(Throwable caught) {
+              // never invoked
+            }
+          });
+    }
   }
 
   private void display(DependencyInfo result) {