[vala] (4 commits) Non-fast-forward update to branch 0.40

[Rico Tzschichholz <ricotz src gnome org>]

The branch '0.40' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  cdad1b9... libvaladoc: Fix ownership declarations of Constants
  d042001... libvaladoc: Drop unused code
  86a2d50... glib-2.0: Guard against passing null source to GLib.Memory.
  0825349... parser: `owned` is not allowed on Constants

Commits added to the branch:

  4530b56... libvaladoc: Fix ownership declarations of Constants
  89172a5... libvaladoc: Drop unused code
  20bd91e... glib-2.0: Guard against passing null source to GLib.Memory.
  8401df9... parser: `owned` is not allowed on Constants