[IMP] test_pylint: do not load default config file

This will avoid useless warning when the file does not exists and
possible false positive errors in case of invalid config in this file.

Also strip output

Cherry-pick of c955c3051c

odoo/addons/test_pylint/tests/test_pylint.py

@@ -122,6 +122,7 @@ class TestPyLint(TransactionCase):
                 paths.append(module_path)
 
         options = [
+            '--rcfile=%s' % os.devnull,
             '--disable=all',
             '--enable=%s' % ','.join(self.ENABLED_CODES),
             '--reports=n',
@@ -146,4 +147,4 @@ class TestPyLint(TransactionCase):
         else:
             out, err = process.communicate()
             if process.returncode:
-                self.fail((b"\n" + out + b"\n" + err).decode('utf-8'))
+                self.fail("pylint test failed:\n" + (b"\n" + out + b"\n" + err).decode('utf-8').strip())