git-status: quote LF in its output

git-status: quote LF in its output

Otherwise, commit log template would get the remainder of the
filename start on a new line unquoted and the log gets messed
up.

I initially considered using the full quote_c_style(), but the
output from the command is primarily for human consumption so
chose to leave other control characters and bytes with high-bits
unmolested.

Signed-off-by: Junio C Hamano <junkio@cox.net>