Merge branch 'rs/cocci'

Code clean-up with help from coccinelle tool continues. * rs/cocci: coccicheck: make transformation for strbuf_addf(sb, "...") more precise use strbuf_add_unique_abbrev() for adding short hashes, part 2 use strbuf_addstr() instead of strbuf_addf() with "%s", part 2 gitignore: ignore output files of coccicheck make target