bpo-38823: Clean up refleaks in _contextvars initialization. (GH-17198)


https://bugs.python.org/issue38823
(cherry picked from commit 143a97f64128070386b12a0ee589bdaad5e51f40)

Co-authored-by: Brandt Bucher <brandtbucher@gmail.com>
diff --git a/Modules/_contextvarsmodule.c b/Modules/_contextvarsmodule.c
index 71dd7fd..1abcdbf 100644
--- a/Modules/_contextvarsmodule.c
+++ b/Modules/_contextvarsmodule.c
@@ -52,6 +52,7 @@
                            (PyObject *)&PyContext_Type) < 0)
     {
         Py_DECREF(&PyContext_Type);
+        Py_DECREF(m);
         return NULL;
     }
 
@@ -60,6 +61,7 @@
                            (PyObject *)&PyContextVar_Type) < 0)
     {
         Py_DECREF(&PyContextVar_Type);
+        Py_DECREF(m);
         return NULL;
     }
 
@@ -68,6 +70,7 @@
                            (PyObject *)&PyContextToken_Type) < 0)
     {
         Py_DECREF(&PyContextToken_Type);
+        Py_DECREF(m);
         return NULL;
     }