[gnome-calculator] tests: add missing os import

[Vadim Rutkovsky <vrutkovsky src gnome org>]

commit d7563e3e042d465daadd26871adc1bec8fb1e105
Author: Vadim Rutkovsky <vrutkovs redhat com>
Date:   Wed Apr 23 23:04:21 2014 +0200

    tests: add missing os import

 tests/environment.py |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/tests/environment.py b/tests/environment.py
index 7807bf0..16daca1 100644
--- a/tests/environment.py
+++ b/tests/environment.py
@@ -7,6 +7,7 @@ if not isA11yEnabled():
 
 from common_steps import App
 from dogtail.config import config
+import os
 
 
 def before_all(context):