[gcr] (3 commits) Non-fast-forward update to branch tintou/fix-certificate-annotations

[Niels De Graef <nielsdg src gnome org>]

The branch 'tintou/fix-certificate-annotations' 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:

  995446c... gcr: Add nullable and out annotations in GcrCertificate

Commits added to the branch:

  5970a45... build: Make building the Vala bindings optional (*)
  1075a31... Merge branch 'vapi-option' into 'master' (*)
  a3f481b... gcr: Add nullable and out annotations in GcrCertificate

(*) This commit already existed in another branch; no separate mail sent