gui: bump theme version to 2

Commit 9472ba1d introduced new behavior for KEY_POWER which
needs a corresponding change in the theme to call the
setbacklight action whenever the power button is pressed.

Change-Id: Iacd46436b04aba1ecb1adbb684c56c3ef994bfe0
diff --git a/gui/theme/portrait_hdpi/ui.xml b/gui/theme/portrait_hdpi/ui.xml
index 67eaa5a..4bce146 100644
--- a/gui/theme/portrait_hdpi/ui.xml
+++ b/gui/theme/portrait_hdpi/ui.xml
@@ -6,7 +6,7 @@
 		<title>Backup Naowz</title>
 		<description>Default basic theme</description>
 		<preview>preview.png</preview>
-		<themeversion>1</themeversion>
+		<themeversion>2</themeversion>
 	</details>
 
 	<include>