revision: read --stdin with strbuf_getline()
Reading with getwholeline() and manually stripping the terminating
'\n' would leave CR at the end of the line if the input comes from
a DOS editor.
Constrasting this with the other changes around "--stdin" in this
series, one may realize that the way "log" family of commands read
the paths with "--stdin" looks inconsistent and sloppy. It does not
allow us to C-quote a textual input, neither does it accept records
that are NUL-terminated. These are unfortunately way too late to
fix X-<.
Signed-off-by: Junio C Hamano <gitster@pobox.com>