QGA VSS: Print error in err_set

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Konstantin Kostiuk <kkostiuk@redhat.com>

qga/vss-win32/requester.cpp

@@ -26,9 +26,11 @@
 
 #define DEFAULT_VSS_BACKUP_TYPE VSS_BT_FULL
 
-#define err_set(e, err, fmt, ...)                                           \
-    ((e)->error_setg_win32_wrapper((e)->errp, __FILE__, __LINE__, __func__, \
-                                   err, fmt, ## __VA_ARGS__))
+#define err_set(e, err, fmt, ...) {                                         \
+    (e)->error_setg_win32_wrapper((e)->errp, __FILE__, __LINE__, __func__,  \
+                                   err, fmt, ## __VA_ARGS__);               \
+    qga_debug(fmt, ## __VA_ARGS__);                                         \
+}
 /* Bad idea, works only when (e)->errp != NULL: */
 #define err_is_set(e) ((e)->errp && *(e)->errp)
 /* To lift this restriction, error_propagate(), like we do in QEMU code */