Fix make_appliance and the libvirt.tmpl

Apparently nobody has used these since the switch to py3, xrange is now
range and it needs to read the file in binary mode when generating the
sha256.

(cherry picked from commit 8e749efbbf)

share/templates.d/99-generic/appliance/libvirt.tmpl

@@ -9,7 +9,7 @@
       <os>
         <loader dev='hd'/>
       </os>
-%for disk, letter in zip(disks, xrange(97, 123)):
+%for disk, letter in zip(disks, range(97, 123)):
       <drive disk='${disk.name}' target='hd${chr(letter)}'/>
 %endfor
     </boot>

src/pylorax/creator.py

@@ -155,7 +155,7 @@ def make_appliance(disk_img, name, template, outfile, networks=None, ram=1024,
 
     log.info("Calculating SHA256 checksum of %s", disk_img)
     sha256 = hashlib.sha256()
-    with open(disk_img) as f:
+    with open(disk_img, "rb") as f:
         while True:
             data = f.read(1024**2)
             if not data: