buildhistory: record tag names and show warning when the same tag corresponds to...

buildhistory: record tag names and show warning when the same tag corresponds to different revision

* persistent cache records tag-srcrev mappings, but is not shared between builders
* when tag is moved in remote repo, all builders should rebuild the component to
  use the same source, show warning when revision is different than what was used
  in last build

(From OE-Core rev: 0bc22ed6bd67031749e8f2cb5415dabf933eef56)

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>