Merge branch 'jk/list-tag-2.7-regression'

"git tag" started listing a tag "foo" as "tags/foo" when a branch
named "foo" exists in the same repository; remove this unnecessary
disambiguation, which is a regression introduced in v2.7.0.

* jk/list-tag-2.7-regression:
tag: do not show ambiguous tag names as "tags/foo"
t6300: use test_atom for some un-modern tests

diff --cc Documentation/git-for-each-ref.txt
Simple merge

diff --cc t/t7004-tag.sh
Simple merge