Fix exception when clicking on binary file without being signed in

The user preferences are only available if the user is signed in.

Change-Id: I2ec307d34464394cd902218a32de1afdf5314f86
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>

gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/PatchTable.java

diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/PatchTable.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/PatchTable.java
index 425309d..638ec13 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/PatchTable.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/PatchTable.java
@@ -268,8 +268,9 @@
       final PatchScreen.Type screenType) {
     if (Dispatcher.isChangeScreen2()) {
       return (patch.getPatchType().equals(PatchType.BINARY)
-          || Gerrit.getUserAccount().getGeneralPreferences().getDiffView()
-          .equals(DiffView.UNIFIED_DIFF));
+          || (Gerrit.isSignedIn()
+              && Gerrit.getUserAccount().getGeneralPreferences().getDiffView()
+                 .equals(DiffView.UNIFIED_DIFF)));
     }
     return screenType == PatchScreen.Type.UNIFIED;
   }