Merge pull request #233 from tianon/docker-dev

Update docker-dev with fewer tags to build (since it doesn't make sense to build/"support" tags that upstream doesn't)

library/docker-dev

@@ -4,13 +4,7 @@ latest: git://github.com/docker/[email protected]
 v1.2.0: git://github.com/docker/[email protected]
 v1.2:   git://github.com/docker/[email protected]
 
-v1.1.2: git://github.com/docker/[email protected]
-v1.1:   git://github.com/docker/[email protected]
-
 v1.0.1: git://github.com/docker/[email protected]
 v1.0:   git://github.com/docker/[email protected]
 
-v0.12.0: git://github.com/docker/[email protected]
-v0.12:   git://github.com/docker/[email protected]
-
-# "supported": one tag per major version, four major versions
+# "supported": one tag per major, only upstream-supported majors