u_boot_pylib: Correct case for test_result

This should be in capitals and defined at the start of the file. Update
it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/buildman/func_test.py b/tools/buildman/func_test.py
index 4e12c67..51a2366 100644
--- a/tools/buildman/func_test.py
+++ b/tools/buildman/func_test.py
@@ -187,7 +187,7 @@
         self._git_dir = os.path.join(self._base_dir, 'src')
         self._buildman_pathname = sys.argv[0]
         self._buildman_dir = os.path.dirname(os.path.realpath(sys.argv[0]))
-        command.test_result = self._HandleCommand
+        command.TEST_RESULT = self._HandleCommand
         bsettings.setup(None)
         bsettings.add_file(settings_data)
         self.setupToolchains()
@@ -266,7 +266,7 @@
         return result
 
     def testFullHelp(self):
-        command.test_result = None
+        command.TEST_RESULT = None
         result = self._RunBuildman('-H')
         help_file = os.path.join(self._buildman_dir, 'README.rst')
         # Remove possible extraneous strings
@@ -277,7 +277,7 @@
         self.assertEqual(0, result.return_code)
 
     def testHelp(self):
-        command.test_result = None
+        command.TEST_RESULT = None
         result = self._RunBuildman('-h')
         help_file = os.path.join(self._buildman_dir, 'README.rst')
         self.assertTrue(len(result.stdout) > 1000)
@@ -286,11 +286,11 @@
 
     def testGitSetup(self):
         """Test gitutils.Setup(), from outside the module itself"""
-        command.test_result = command.CommandResult(return_code=1)
+        command.TEST_RESULT = command.CommandResult(return_code=1)
         gitutil.setup()
         self.assertEqual(gitutil.use_no_decorate, False)
 
-        command.test_result = command.CommandResult(return_code=0)
+        command.TEST_RESULT = command.CommandResult(return_code=0)
         gitutil.setup()
         self.assertEqual(gitutil.use_no_decorate, True)