lxd: Prevents overwriting instances with same name but different project.
lxd: Prevents overwriting instances with same name but different project.

When fetching instance data a map of instance names was used to track
concurrent requests. However, instance names are not globally unique and
when "all-projects=true" instances were being overwritten in the map.

Signed-off-by: Mark Laing <e4eb1ed17d42befab1db63da5bbc17c0a2c16113@canonical.com>

lxc/lxd,hallyn/lxd,lxc/lxd,stgraber/lxd,hallyn/lxd,stgraber/lxd,stgraber/lxd,stgraber/lxd,hallyn/lxd,lxc/lxd,lxc/lxd,lxc/lxd,stgraber/lxd,hallyn/lxd,stgraber/lxd,hallyn/lxd,stgraber/lxd,lxc/lxd,lxc/lxd,hallyn/lxd