Turns out that 'is_empty' comes from arches... who knew? I didn't

Signed-off-by: Patrick Uiterwijk <puiterwijk@redhat.com>

roles/bodhi2/backend/templates/variants.rpm.xml.j2

@@ -22,13 +22,4 @@
 	    [% endif %]
         </arches>
     </variant>
-    [% if release.version_int >= 28 %]
-        <variant id="Everything" name="Everything" type="variant">
-            <arches>
-                <arch>x86_64</arch>
-                <arch>ppc64le</arch>
-                <arch>aarch64</arch>
-	    </arches>
-	</variant>
-    [% endif %]
 </variants>