remote.<remote>.vcs causes remote->foreign_vcs to be set on entry to
transport_get(). Unfortunately, the code assumed that any such entry
is stale from previous round.
Fix this by making VCS set by URL to be volatile w.r.t. transport_get()
instead.
Signed-off-by: Ilari Liusvaara <ilari.liusvaara@elisanet.fi> Acked-by: Daniel Barkalow <barkalow@iabervon.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>