make it python 2 compatible

Author: rakshith91

tools/azure-devtools/src/azure_devtools/scenario_tests/utilities.py

@@ -70,7 +70,10 @@ def trim_kwargs_from_test_function(fn, kwargs):
     # the next function is the actual test function. the kwargs need to be trimmed so
     # that parameters which are not required will not be passed to it.
     if not is_preparer_func(fn):
-        args, _, kw, _, _, _, _ = inspect.getfullargspec(fn)
+        try:
+            args, _, kw, _, _, _, _ = inspect.getfullargspec(fn)
+        except AttributeError:
+            args, _, kw, _ = inspect.getargspec(fn) # pylint: disable=deprecated-method
         if kw is None:
             args = set(args)
             for key in [k for k in kwargs if k not in args]: