remote-curl: avoid truncating refs with ls-remote

remote-curl: avoid truncating refs with ls-remote

Normally, the remote-curl transport helper is aware of the hash
algorithm we're using because we're in a repo with the appropriate hash
algorithm set. However, when using git ls-remote outside of a
repository, we won't have initialized the hash algorithm properly, so
use hash_to_hex_algop to print the ref corresponding to the algorithm
we've detected.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>