Simplify condition

Author: lesteve

_pytest/recwarn.py

@@ -216,8 +216,8 @@ def __exit__(self, *exc_info):
         # only check if we're not currently handling an exception
         if all(a is None for a in exc_info):
             if self.expected_warning is not None:
-                if not any(issubclass(r.category, exp_warning) for
-                           exp_warning in self.expected_warning for r in self):
+                if not any(issubclass(r.category, self.expected_warning)
+                           for r in self):
                     __tracebackhide__ = True
                     pytest.fail("DID NOT WARN. No warnings of type {0} was emitted. "
                                 "The list of emitted warnings is: {1}.".format(