Fixed an unused variable warning introduced in GH-6800 (GH-6816)

(cherry picked from commit 00717a46a120dd8c8c74970fd75d201a5f42ab18)

Co-authored-by: Alex Gaynor <alex.gaynor@gmail.com>
diff --git a/Modules/_ssl.c b/Modules/_ssl.c
index 650f030..7670833 100644
--- a/Modules/_ssl.c
+++ b/Modules/_ssl.c
@@ -882,7 +882,6 @@
 {
     PySSLSocket *self;
     SSL_CTX *ctx = sslctx->ctx;
-    long mode;
 
     self = PyObject_New(PySSLSocket, &PySSLSocket_Type);
     if (self == NULL)