[FIX] web: false id should remain false in evalContext

'id' is a particular field that should not be considered like other
integer fields. For instance, in the evalContext, its value should
not fallback to 0 if it is false. This would break domains in attrs
like ['id', '=', False], which is supposed to be true on new (not
saved yet) records.

This was for example the case in the Product form view: go to Sales
Orders form view, add a line, on the product field choose 'Create
and Edit', try to save the product -> error: field Product Template
is required but not set (actually it is invisible), as its required
modifier says ['id', '!=', False], which was always the case.

addons/web/static/src/js/views/basic/basic_model.js

@@ -2176,7 +2176,7 @@ var BasicModel = AbstractModel.extend({
             if (context[fieldName] === null) {
                 context[fieldName] = false;
             }
-            if (!field) {
+            if (!field || field.name === 'id') {
                 continue;
             }
             if (field.type === 'float' ||

addons/web/static/tests/views/form_tests.js

@@ -5039,5 +5039,30 @@ QUnit.module('Views', {
 
         form.destroy();
     });
+
+    QUnit.test('id is False in evalContext for new records', function (assert) {
+        assert.expect(2);
+
+        var form = createView({
+            View: FormView,
+            model: 'partner',
+            data: this.data,
+            arch: '<form string="Partners">' +
+                        '<field name="id"/>' +
+                        '<field name="foo" attrs="{\'readonly\': [[\'id\', \'=\', False]]}"/>' +
+                '</form>',
+        });
+
+        assert.ok(form.$('.o_field_widget[name=foo]').hasClass('o_readonly_modifier'),
+            "foo should be readonly in 'Create' mode");
+
+        form.$buttons.find('.o_form_button_save').click();
+        form.$buttons.find('.o_form_button_edit').click();
+
+        assert.notOk(form.$('.o_field_widget[name=foo]').hasClass('o_readonly_modifier'),
+            "foo should not be readonly anymore");
+
+        form.destroy();
+    });
 });
 });