Sync with 2.3.10

Documentation/RelNotes/2.3.10.txt

Documentation/git.txt

builtin/blame.c

builtin/merge-file.c

builtin/merge-tree.c

builtin/rerere.c

combine-diff.c

connect.c

diff.c

diffcore-pickaxe.c

git-submodule.sh

http.c

line-log.c

ll-merge.c

t/lib-httpd/apache.conf

t/lib-proto-disable.sh

t/t5810-proto-disable-local.sh

t/t5811-proto-disable-git.sh

t/t5812-proto-disable-http.sh

t/t5813-proto-disable-ssh.sh