Merge branch 'jc/hash-object' into maint

"hash-object --literally" introduced in v2.2 was not prepared to take a really long object type name. * jc/hash-object: write_sha1_file(): do not use a separate sha1[] array t1007: add hash-object --literally tests hash-object --literally: fix buffer overrun with extra-long object type git-hash-object.txt: document --literally option