Adapt to work with x64 builds

packages/firefox-config.xml

@@ -8,11 +8,9 @@
 
         <depends package-id="firefox" />
 
-        <variable name='PKG_VERSION' value='6' />
-        <variable architecture='x86' name='PROG' value='%PROGRAMFILES%\Mozilla Firefox' />
-        <variable architecture='x64' name='PROG' value='%PROGRAMFILES(x86)%\Mozilla Firefox' />
-        <variable architecture='x86' name='REG_PATH' value='HKLM\Software\Mozilla\Firefox' />
-        <variable architecture='x64' name='REG_PATH' value='HKLM\Software\Wow6432Node\Mozilla\Firefox' />
+        <variable name='PKG_VERSION' value='7' />
+        <variable name='PROG' value='%PROGRAMFILES%\Mozilla Firefox' />
+        <variable name='REG_PATH' value='HKLM\Software\Mozilla\Firefox' />
 
         <check type="registry" condition="equals" path="%REG_PATH%\ConfigRevision" value="%PKG_VERSION%" />