utils: Set default values for position and duration query results

https://bugzilla.gnome.org/show_bug.cgi?id=797066
diff --git a/gst/gstutils.c b/gst/gstutils.c
index 13c1bcd..0961f64 100644
--- a/gst/gstutils.c
+++ b/gst/gstutils.c
@@ -2428,6 +2428,9 @@
   GstQuery *query;
   gboolean ret;
 
+  if (cur != NULL)
+    *cur = GST_CLOCK_TIME_NONE;
+
   g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
   g_return_val_if_fail (format != GST_FORMAT_UNDEFINED, FALSE);
 
@@ -2466,6 +2469,9 @@
   GstQuery *query;
   gboolean ret;
 
+  if (duration != NULL)
+    *duration = GST_CLOCK_TIME_NONE;
+
   g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
   g_return_val_if_fail (format != GST_FORMAT_UNDEFINED, FALSE);
 
@@ -2836,6 +2842,9 @@
   GstQuery *query;
   gboolean ret;
 
+  if (cur != NULL)
+    *cur = GST_CLOCK_TIME_NONE;
+
   g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
   g_return_val_if_fail (format != GST_FORMAT_UNDEFINED, FALSE);
 
@@ -2865,6 +2874,9 @@
   GstQuery *query;
   gboolean ret = FALSE;
 
+  if (cur != NULL)
+    *cur = GST_CLOCK_TIME_NONE;
+
   g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
   g_return_val_if_fail (format != GST_FORMAT_UNDEFINED, FALSE);
 
@@ -2893,6 +2905,9 @@
   GstQuery *query;
   gboolean ret;
 
+  if (duration != NULL)
+    *duration = GST_CLOCK_TIME_NONE;
+
   g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
   g_return_val_if_fail (format != GST_FORMAT_UNDEFINED, FALSE);
 
@@ -2922,6 +2937,9 @@
   GstQuery *query;
   gboolean ret = FALSE;
 
+  if (duration != NULL)
+    *duration = GST_CLOCK_TIME_NONE;
+
   g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
   g_return_val_if_fail (GST_PAD_IS_SINK (pad), FALSE);
   g_return_val_if_fail (format != GST_FORMAT_UNDEFINED, FALSE);