Fix file leak in test program

A similar bug was fixed earlier in ssl_server2, but we missed the fix
in ssl_client2.
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index 8f0d3b5..c188900 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -619,6 +619,7 @@
         if( fwrite( nss_keylog_line, 1, len, f ) != len )
         {
             ret = -1;
+            fclose( f );
             goto exit;
         }