Doing so would be incoherent since --get-color would pick a color slot
and ignore the variable type option (e.g. --bool), and the type would
require a variable name.
Suggested by Junio C Hamano.
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>