[libvirt] [PATCH 5/5]: Rewrite findLuns function

This rather large patch rewrites the virStorageBackendISCSIFindLUNs() function to only rely on sysfs for finding LUNs, given a session number. Along the way, it also fixes the bug where we wouldn't find LUNs for older kernels (with the block:sda format), and also (possibly) fixes a race condition where we could try to find the LUN before udev has finished connecting it. I say it "possibly" fixes it because I haven't been able to hit it so far, but I definitely need more testing to try and confirm. Changes since last time: 1) Don't blindly ignore the 0'th LUN (thanks Stefan). Instead, look if the LUNs are Direct-Access devices (as defined by the kernel); if so, they are LUNs we can use. 2) Fix up whitespace damage. 3) Check the return value of the scsidev strdup as pointed out by Jim. 4) Change all ISCSIADM commands to be const char *const as pointed out by Jim. Signed-off-by: Chris Lalancette <clalance(a)redhat.com&gt;