Remove unused assignment (#3519)

diff --git a/src/cryptography/utils.py b/src/cryptography/utils.py
index 6d30485..40359c6 100644
--- a/src/cryptography/utils.py
+++ b/src/cryptography/utils.py
@@ -144,5 +144,5 @@
 def deprecated(value, module_name, message, warning_class):
     module = sys.modules[module_name]
     if not isinstance(module, _ModuleWithDeprecations):
-        sys.modules[module_name] = module = _ModuleWithDeprecations(module)
+        sys.modules[module_name] = _ModuleWithDeprecations(module)
     return _DeprecatedValue(value, message, warning_class)