test/py: fix printenv signon message disable code

CONFIG_VERSION_VARIABLE isn't always defined, so we can't simply look up
its value directly, or an exception will occur if it isn't defined.
Instead, we must use .get() to supply a default value if the variable
isn't defined.

Fixes: da37f006 ("tests: py: disable main_signon check for printenv cmd")
Acked-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

test/py/tests/test_env.py

@@ -39,7 +39,8 @@ class StateTestEnv(object):
             Nothing.
         """
 
-        if self.u_boot_console.config.buildconfig['config_version_variable'] == 'y':
+        if self.u_boot_console.config.buildconfig.get(
+                'config_version_variable', 'n') == 'y':
             with self.u_boot_console.disable_check('main_signon'):
                 response = self.u_boot_console.run_command('printenv')
         else: