ls-remote: run setup_git_directory_gently() sooner

ls-remote: run setup_git_directory_gently() sooner

ls-remote already runs a repository search unconditionally to learn
about remote nicknames and "[url] insteadof" shortcuts.  Run that
search a little sooner, and now one can try

	[pager]
		ls-remote

to automatically paginate ls-remote output, or use repository-local

	[core]
		pager = whatever

with "git --paginate ls-remote <url>".

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>