Fixing 2 minor issues as suggested by Gunan.

Update release note.

Bump the version of nccl for macos fixes.

Improve upgrade script to handle list comprehensions as arguments. (t…

…ensorflow#7229)

python's ast module does not return the correct location, so we
have to do our best to scan backwards to find where the [ token
that trully started the list comprehension occurs.

Add 3.3 and 3.6 binary URLs to installation instruction. (tensorflow#…

…7085)

Update release notes for 1.0.0-alpha. (tensorflow#6747)

* Update release notes for 1.0.0-alpha.

* Add numpy compatibility to release notes.

Merge pull request tensorflow#6491 from gunan/patch

patches for 0.12.1 release.

Update cudnn version in instruction for mac gpu. (tensorflow#6407)

Update installation instructions for tensorflow-gpu. (tensorflow#6231)

* Update installation instructions for tensorflow-gpu.

* Update os_setup.md

Update release note for tensorboard (tensorflow#5916)