Merge pull request tensorflow#1456 from vinuraja/releng_20191008_182935

Update version for 1.15.0-rc2 release.

Merge pull request tensorflow#1446 from minglotus-6/releng_20190924_1…

…15434

Update version for 1.15.0-rc1 release.

Merge pull request tensorflow#1391 from lilao/releng_20190708_082757

Update version for 1.12.3 release.

Merge pull request tensorflow#1390 from christisg/releng_20190628_110321

Update version for 1.14.0 release.

Merge pull request tensorflow#1373 from netfs/cpr1.14

Merge pull request tensorflow#1367 from ashahba:ashahba/future

Merge pull request tensorflow#1268 from netfs/releng_20190225_145024

Update version for 1.13.0 release.

Merge pull request tensorflow#1260 from lilao/releng_20190213_114258

Update version for 1.13.0-rc1 release.

Merge pull request tensorflow#1172 from netfs/releng_20181106_095039

Update version for 1.12.0 release.

Merge pull request tensorflow#1164 from netfs/releng_20181026_132728

Update version for 1.12.0-rc0 release.

Merge pull request tensorflow#1154 from netfs/releng_20181023_120926

Update version for 1.11.1 release.