Test that git-branch -l works.

Test that git-branch -l works.

If the user supplies -l to git-branch when creating a new branch
then the new branch's log should be created automatically and the
branch creation should be logged in that log.

Further if a branch is being deleted and it had a log then also
verify that the log was deleted.

Test git-checkout -b foo -l for creating a new branch foo with a
log and checking out that branch.

Fixed git-checkout -b foo -l as the branch variable name was
incorrect in the script.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>