[ostree] Created tag v2015.9

[Colin Walters <walters src gnome org>]

The signed tag 'v2015.9' was created.

Tagger: Colin Walters <walters verbum org>
Date: Wed Sep 23 12:16:24 2015 -0400

    Release 2015.9
    
    There aren't any major new features, but this release has some notable
    bugfixes.  For example, 2015.8 broke xdg-app due to an internal
    change in how mainloop contexts were handled for pull - that's now fixed.
    
    Another notable change is a new API `ostree_sysroot_prepare_cleanup()` which
    is now used by `ostree admin deploy`.  What this enables is to do:
    
    ```
    ostree pull repo:$commitid
    ostree admin deploy repo:$commitid
    ```
    
    Before this, `admin deploy` would prune the repository, removing the
    un-referenced commit.
    
    In other words, you can now more easily pull the exact (possibly
    older) commit you want and deploy it.
    
    New contributors:
    
     - Leandro Santiago
     - Gatis Paeglis
    
    Bugfixes from:
    
     - Alexander Larsson
     - Colin Walters
     - Giuseppe Scrivano
     - Matthew Barnes
    
    Git-EVTag-v0-SHA512: 
d528475ccdc65a882cdda8d2a5f9b1925a599d65b51207e2dace4a4a3ea14a71d5f1dc6803077d1b62b51ac7b03816b249a982d8da074ddbe198accd8476c341

Changes since the last tag 'v2015.8':

Alexander Larsson (2):
      offline delta apply: Handle the version field
      _ostree_static_delta_part_validate: Take a stream instead of a file as arg

Colin Walters (5):
      fetcher: Use 0666 (-umask) for temporary files
      pull: Only fetch all refs if we're mirroring
      pull: Go back to using one main context
      tests: Add a test for static-delta apply-offline
      Release 2015.9

Gatis Paeglis (1):
      Remove unused variables

Giuseppe Scrivano (1):
      pull: honor gpg-verify-summary=false when a summary signature is present

Leandro Santiago (1):
      Mutable is a keyword in C++11

Matthew Barnes (7):
      commit: Clarify reasoning for "commit-update-summary" default
      sysroot: Add ostree_sysroot_prepare_cleanup()
      deploy: Do not prune repository
      libglnx: Update from master
      reset: Simplify argument checking logic
      repo: Fix build without libsoup
      pull: Honor depth with OSTREE_REPO_PULL_FLAGS_COMMIT_ONLY