simplify annotationsFutureEnabled (#909)

pyflakes/checker.py

diff --git a/pyflakes/checker.py b/pyflakes/checker.py
index f8eef75..02bb30c 100644
--- a/pyflakes/checker.py
+++ b/pyflakes/checker.py
@@ -794,9 +794,7 @@
     @property
     def annotationsFutureEnabled(self):
         scope = self.scopeStack[0]
-        if not isinstance(scope, ModuleScope):
-            return False
-        return scope._annotations_future_enabled
+        return isinstance(scope, ModuleScope) and scope._annotations_future_enabled
 
     @annotationsFutureEnabled.setter
     def annotationsFutureEnabled(self, value):