blame.c: Properly initialize strbuf after calling textconv_object(), again
blame.c: Properly initialize strbuf after calling textconv_object(), again

2564aa4 started to initialize buf.alloc, but that should actually be one
more byte than the string length due to the trailing \0. Also, do not
modify buf.alloc out of the strbuf code. Use the existing strbuf_attach
instead.

Signed-off-by: Sebastian Schuberth <77397652b38ec60b50e56236b813774ce842bcdf@gmail.com>
Reviewed-by: Jeff King <696e3fbcf235d40b6ea1ebd61c87cbea79d444e7@peff.net>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git