t4150: test applying StGit series
A StGit series is a directory containing a "series" file which begins
with the line:
# This series applies on GIT commit XXXXX
where XXXXX is the commit ID that the patch series applies on. Every
following line names a patch in the directory to be applied.
Test that git-am, when given this "series" file, is able to detect it as
an StGit series and apply all the patches in the series.
Signed-off-by: Paul Tan <pyokagan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>