Merge branch 'rs/cocci' into maint

Code cleanup. * rs/cocci: use strbuf_add_unique_abbrev() for adding short hashes, part 3 remove unnecessary NULL check before free(3) 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 use strbuf_addstr() for adding constant strings to a strbuf, part 2 add coccicheck make target contrib/coccinelle: fix semantic patch for oid_to_hex_r()