The udev and hal drivers both already call the same functions as these
new functions added to node_device_linux_sysfs.c, but 1) we need to
call them from node_device_driver.c, and 2) it would be nice to
eliminate the duplicated code from the hal and udev backends.
This file contains only a single function, detect_scsi_host_caps(),
which is declared in node_device_driver.h and called from both the hal
and udev backends. Other things common to the hal and udev drivers
can be placed in that file though. As a prelude to adding further
functions, this patch renames the existing function to something
closer in line with other internal libvirt function names
(nodeDeviceSysfsGetSCSIHostCaps()), and puts the declarations into a
separate .h file.