Fix a global var bug..

git-svn-id: https://redmine.imt-atlantique.fr/svn/xaal/code/Python/branches/fork@1509 b32b6428-25c9-4566-ad07-03861ab6144f

apps/tools/xaal/tools/tail.py

@@ -67,6 +67,7 @@ def usage():
 
 
 def main():
+    global level
     if len(sys.argv) == 2:
         level = int(sys.argv[1])