Fix e2e test for py ver < 3.3

Signed-off-by: javrin <jawabiscuit@users.noreply.github.com>

src/rez/tests/test_e2e_shells.py

@@ -8,6 +8,7 @@
 from __future__ import print_function
 import json
 import os
+import sys
 from fnmatch import fnmatch
 from textwrap import dedent
 
@@ -204,6 +205,10 @@ def test_shell_invoking_script(self, shell):
         self.assertEqual(p.returncode, 0)
         assert stderr is None
 
+        # Popen args added in v3.3
+        if sys.version_info < (3, 3):
+            return
+
         lines = []
         script_arg = next(iter(arg for arg in p.args if "rez-shell" in arg))
         exec_script = next(iter(arg for arg in script_arg.split() if "rez-shell" in arg))