Merge branch 'rs/use-strbuf-addstr'

* rs/use-strbuf-addstr:
use strbuf_addstr() instead of strbuf_addf() with "%s"
use strbuf_addstr() for adding constant strings to a strbuf

diff --cc http-push.c
Simple merge

diff --cc http.c
Simple merge

diff --cc send-pack.c
Simple merge

diff --cc sequencer.c
Simple merge

diff --cc t/helper/test-run-command.c
Simple merge