BUG/MINOR: ssl: typo in previous patch

The previous patch 5c3c96f ("BUG/MINOR: ssl: memory leak w/ the
ocsp_issuer") contains a typo that prevent it to build.

Should be backported in 2.1.
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index 38e95fa..afcceae 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -3128,7 +3128,7 @@
 	}
 
 	if (ckch->ocsp_issuer)
-		X509_free(ocsp_issuer);
+		X509_free(ckch->ocsp_issuer);
 	ckch->ocsp_issuer = NULL;
 }