qmicli,helpers: make sure flags are reset before parsing the string

We OR each flag value found in the output directly, so make sure that
output is clear before adding any new flag.

Reported-by: Paul Gildea <gildeap@tcd.ie>
diff --git a/src/qmicli/qmicli-helpers.c b/src/qmicli/qmicli-helpers.c
index 2a2dad2..46e17db 100644
--- a/src/qmicli/qmicli-helpers.c
+++ b/src/qmicli/qmicli-helpers.c
@@ -237,6 +237,8 @@
     type = qmi_nas_rat_mode_preference_get_type ();
     flags_class = G_FLAGS_CLASS (g_type_class_ref (type));
 
+    *out = 0;
+
     items = g_strsplit_set (str, "|", 0);
     for (iter = items; iter && *iter && success; iter++) {
         if (!*iter[0])
@@ -451,6 +453,8 @@
     type = qmi_device_open_flags_get_type ();
     flags_class = G_FLAGS_CLASS (g_type_class_ref (type));
 
+    *out = 0;
+
     items = g_strsplit_set (str, "|", 0);
     for (iter = items; iter && *iter && success; iter++) {
         if (!*iter[0])