Selenium - fix rerunning test errors for test_custom_builds.

Fixed similar problem for saved histories tests with 3416674. Should fix this problem https://jenkins.galaxyproject.org/job/selenium/568/artifact/568-test-errors/test_build_delete2017092319091506208182/stacktrace.txt.

test/selenium_tests/test_custom_builds.py

@@ -9,19 +9,19 @@
 
 class CustomBuildsTestcase(SharedStateSeleniumTestCase):
 
-    def setUp(self):
-        super(CustomBuildsTestcase, self).setUp()
-        self.home()  # ensure Galaxy is loaded
-        self.submit_login(self.user_email, retries=2)
-
     @selenium_test
     def test_build_add(self):
+        self._login()
+
         self.navigate_to_custom_builds_page()
+
         self.add_custom_build(self.build_name1, self.build_key1)
         self.assert_custom_builds_in_grid([self.build_name1])
 
     @selenium_test
     def test_build_delete(self):
+        self._login()
+
         self.navigate_to_custom_builds_page()
 
         self.add_custom_build(self.build_name2, self.build_key2)
@@ -39,6 +39,10 @@ def assert_custom_builds_in_grid(self, expected_builds, present=True):
         else:
             self.assertEqual(intersection, set())
 
+    def _login(self):
+        self.home()  # ensure Galaxy is loaded
+        self.submit_login(self.user_email, retries=2)
+
     def add_custom_build(self, build_name, build_key):
         name_div = self.wait_for_selector('div[tour_id="name"')
         name_input = name_div.find_element_by_css_selector('.ui-form-field input')