Python: Fix minor problems in security examples

python/ql/src/Security/CWE-022/examples/tainted_path.py

@@ -11,7 +11,6 @@ urlpatterns = [
 
 def user_picture1(request):
     """A view that is vulnerable to malicious file access."""
-    base_path = '/server/static/images'
     filename = request.GET.get('p')
     # BAD: This could read any file on the file system
     data = open(filename, 'rb').read()

python/ql/src/Security/CWE-078/examples/command_injection.py

@@ -20,5 +20,4 @@ def command_execution_safe(request):
     if request.method == 'POST':
         action = request.POST.get('action', '')
         #GOOD -- Use a whitelist
-        subprocess.call(["application", COMMAND[action]])
-
+        subprocess.call(["application", COMMANDS[action]])