Merge branch 'jc/describe-misnamed-annotated-tag'

When "git describe C" finds an annotated tag with tagname A to be
the best name to explain commit C, and the tag is stored in a
"wrong" place in the refs/tags hierarchy, e.g. refs/tags/B, the
command gave a warning message but used A (not B) to describe C.
If C is exactly at the tag, the describe output would be "A", but
"git rev-parse A^0" would not be equal as "git rev-parse C^0".  The
behavior of the command has been changed to use the "long" form
i.e. A-0-gOBJECTNAME, which is correctly interpreted by rev-parse.

* jc/describe-misnamed-annotated-tag:
  describe: force long format for a name based on a mislocated tag

diff --cc builtin/describe.c
Simple merge

diff --cc t/t6120-describe.sh
Simple merge