console: fix error-code inversion

The error-code propagated via sysview is always negative. Avoid
multiplying by -1 before returning it. Otherwise, we will return >0
instead of <0, which will not be detected as error by sysview-core.

src/console/consoled-manager.c

@@ -225,7 +225,7 @@ static int manager_sysview_session_control(Manager *m, sysview_event *event) {
                                 sysview_session_get_name(session));
                 session_free(s);
                 sysview_session_set_userdata(session, NULL);
-                return -error;
+                return error;
         }
 
         return 0;