tools/hotplug: Removing of "all" dependency from "install" rule.

tools/hotplug: Removing of "all" dependency from "install" rule.

The "install" rules depends on both "all" and "subdirs-install" and
"all" depends on "subdirs-all". This leads the "install" rules to call
both "subdirs-all" and "subdirs-install" which create a race with two
concurrent `make` within the same directory (systemd) trying to make the
same things (xen.conf) and failing.

Ultimatly, "install" should only depend on the things it needs to
install, and not on "all".

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Tested-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>