git-clone: tell the user a bit more about clone-pack failure.
When clone-pack has trouble with the remote, it dies unfriendly
"EOF" error message. We cannot tell the reason why it failed
from the local end; it could be that the repository did not
exist, or configured not to serve over git-daemon, or a network
failure. At least, saying clone-pack failed makes it a bit more
meaningful.
I am not convinced yet that removing the newly created directory
is the right thing to do, so this commit leaves the new
directory behind.
Reported by Sam Ravnborg.
Signed-off-by: Junio C Hamano <junkio@cox.net>