If you have local changes that don't conflict with the
branch-switching changes, these should be kept, not cause errors even
without -m, and be reported afterwards in name-status format.
With -m, the changes carried across should be listed as well. And, for
now, include the merge-recursive output from this process.
Also test the detatched head message in at least one case.
Signed-off-by: Daniel Barkalow <barkalow@iabervon.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>