[PATCH 2/2] sim7100: fix AT chat leak on PPP open failure

If opening the PPP channel fails in sim7100_enable(), the previously
opened AT chat instance is not released, resulting in a resource leak.

Fix this by unref'ing the AT chat and clearing the pointer before
returning the error.
---
 plugins/sim7100.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/plugins/sim7100.c b/plugins/sim7100.c
index 4148e0b2..169b6b47 100644
--- a/plugins/sim7100.c
+++ b/plugins/sim7100.c
@@ -272,8 +272,11 @@ static int sim7100_enable(struct ofono_modem *modem)
 		return err;
 
 	err = open_device(modem, "PPP", &data->ppp);
-	if (err < 0)
+	if (err < 0) {
+		g_at_chat_unref(data->at);
+		data->at = NULL;
 		return err;
+	}
 
 	data->init_count = 0;
 	data->init_cmd = g_at_chat_send(data->at, "AT", NULL,
-- 
2.52.0