Remove duplicate imports/unused variable

gluon/compileapp.py

@@ -532,7 +532,7 @@ def run_models_in(environment):
 
     folder = environment['request'].folder
     c = environment['request'].controller
-    f = environment['request'].function
+    #f = environment['request'].function
     response = environment['response']
 
     path = pjoin(folder, 'models')

gluon/restricted.py

@@ -236,8 +236,6 @@ def restricted(code, environment=None, layer='Unknown'):
 
 def snapshot(info=None, context=5, code=None, environment=None):
     """Return a dict describing a given traceback (based on cgitb.text)."""
-    import os
-    import types
     import time
     import linecache
     import inspect

gluon/sqlhtml.py

@@ -1641,7 +1641,6 @@ class SQLFORM(FORM):
 
     @staticmethod
     def smartdictform(session, name, filename=None, query=None, **kwargs):
-        import os
         if query:
             session[name] = query.db(query).select().first().as_dict()
         elif os.path.exists(filename):