qemu_hotplug: make Detach functions called only from qemu_hotplug.c static

qemu_hotplug: make Detach functions called only from qemu_hotplug.c static

These are no longer called from qemu_driver.c, since the function that
called them (qemuDomainDetachDeviceLive()) has been moved to
qemu_hotplug.c, and they are no longer called from testqemuhotplug.c
because it now just called qemuDomainDetachDeviceLive() instead of all
the subordinate functions.

Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>