fix broken test and personas (bug 576732)

apps/addons/templates/addons/button.html

@@ -1,5 +1,5 @@
 {% set b = button %}
-{% set compat = version.compatible_apps[APP] %}
+{% set compat = version.compatible_apps[APP] if version else {} %}
 
 <div class="install-shell">
 <div class="install {{ b.install_class|join(' ') }}"

apps/addons/tests/test_buttons.py

@@ -399,7 +399,7 @@ class TestButtonHtml(ButtonTest):
         compat = Mock()
         compat.min.version = 'min version'
         compat.max.version = 'max version'
-        self.addon.compatible_apps = {amo.FIREFOX: compat}
+        self.version.compatible_apps = {amo.FIREFOX: compat}
         install = self.render()('.install')
         eq_('min version', install.attr('data-min'))
         eq_('max version', install.attr('data-max'))