convert_to_git sets src=dst->buf if any of the preceding conversions
actually did any work. Thus in ident_to_git we have to use memmove
instead of memcpy as far as src->dst copying is concerned.
Signed-off-by: Thomas Rast <trast@student.ethz.ch> Signed-off-by: Junio C Hamano <gitster@pobox.com>