We can now easily fetch and merge things from heads in the
refs/remotes/ hierarchy in remote repositories.

The refs/remotes/ hierarchy is likely to become the standard for
tracking foreign SCMs, as well as the location of Pull: targets
for tracking remote branches in newly cloned repositories.
Signed-off-by: NEric Wong <normalperson@yhbt.net>
Signed-off-by: NJunio C Hamano <junkio@cox.net>