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
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com> Signed-off-by: Saul Wold <sgw@linux.intel.com>
