Don't consider as unique clause with nested target

issue4552
review11161002

src/common.js

@@ -1846,6 +1846,7 @@
         unique_value: function(domain) {
             if ((domain instanceof Array) &&
                     (domain.length == 1) &&
+                    !domain[0][0].contains('.') &&
                     (domain[0][1] == '=')) {
                 return [true, domain[0][1], domain[0][2]];
             } else {

tests/sao.js

@@ -1878,6 +1878,8 @@
         QUnit.ok(!unique_value(domain)[0]);
         domain = [['a', '=', 1], ['a', '=', 2]];
         QUnit.ok(!unique_value(domain)[0]);
+        domain = [['a.b', '=', 1]];
+        QUnit.ok(!unique_value(domain)[0]);
     });
 
     QUnit.test('DomainInversion evaldomain', function() {