* stable-2.16:
js.bzl: Avoid using deprecated depset union
gwt.bzl: Avoid using deprecated depset union
classpath.bzl: Avoid using deprecated depset union
javadoc.bzl: Avoid using deprecated depset union
pkg_war.bzl: Avoid using deprecated depset union
Update rules_closure to make it forward compatible
Change-Id: I3ebe45fae1acd7e531a09bda59a3a1cd577ca218