BUG/MINOR: ssl: memory leak w/ the ocsp_issuer

This patch frees the ocsp_issuer in
ssl_sock_free_cert_key_and_chain_contents().

Shoudl be backported in 2.1.
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index db9621b..38e95fa 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -3126,6 +3126,10 @@
 		free(ckch->ocsp_response);
 		ckch->ocsp_response = NULL;
 	}
+
+	if (ckch->ocsp_issuer)
+		X509_free(ocsp_issuer);
+	ckch->ocsp_issuer = NULL;
 }
 
 /*