[gnome-software] Fix crash when no plugin performs purchase

[Robert Ancell <rancell src gnome org>]

commit 912451c69319a39cc10f58dd55b31a98c0cf6d9c
Author: Robert Ancell <robert ancell canonical com>
Date:   Wed Jan 24 15:53:38 2018 +1300

    Fix crash when no plugin performs purchase

 src/gs-page.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/src/gs-page.c b/src/gs-page.c
index 6102303..b755580 100644
--- a/src/gs-page.c
+++ b/src/gs-page.c
@@ -360,9 +360,8 @@ gs_page_app_purchased_cb (GObject *source,
        }
 
        if (gs_app_get_state (helper->app) != AS_APP_STATE_AVAILABLE) {
-               g_warning ("no plugin purchased %s: %s",
-                          gs_app_get_id (helper->app),
-                          error->message);
+               g_warning ("no plugin purchased %s",
+                          gs_app_get_id (helper->app));
                return;
        }