Make JGit describe behaves same as c-git for lightweight tags

Make JGit describe behaves same as c-git for lightweight tags

JGit now considers lightweight tags only if the --tags option is set
i.e. `git.describe().setAllTags(true)` has to be set, else the default
is now as in c git:

Only annotated tags are evaluated unless you pass true
equivalent to --tags (or --all) by the option setAllTags.

Hint: This (still) doesn't address any difference between c-git
`--all` and `!--all --tags` behavior;
perhaps this might be a follow up request

Bug: 423206
Change-Id: I9a3699756df0b9c6a7c74a7e8887dea0df17c8e7
Signed-off-by: Marcel Trautwein <me+eclipse@childno.de>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>