Fix "Show Tabs" checkbox

The box wasn't connected back to its underlying model, so toggling
it had no effect.

Change-Id: I7616dbb6d5fc595c293d92569bf5aa6e6dd49f18
Signed-off-by: Shawn O. Pearce <sop@google.com>
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/patches/PatchScriptSettingsPanel.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/patches/PatchScriptSettingsPanel.java
index 4921f4a..d1ce86b 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/patches/PatchScriptSettingsPanel.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/patches/PatchScriptSettingsPanel.java
@@ -181,7 +181,7 @@
     p.setSyntaxHighlighting(syntaxHighlighting.getValue());
     p.setIntralineDifference(intralineDifference.getValue());
     p.setShowWhiteSpaceErrors(whitespaceErrors.getValue());
-    p.setShowTabs(p.isShowTabs());
+    p.setShowTabs(showTabs.getValue());
 
     value = s;
     fireEvent(new ValueChangeEvent<PatchScriptSettings>(s) {});