Checksum fix

disk.py

@@ -59,9 +59,12 @@ class Disk(object):
 
     @property
     def checksum(self, blocksize=65536):
+        logging.debug("Generating checksum for %s", self.get_path())
         hash = md5()
         with open(self.get_path(), "rb") as f:
             for block in iter(lambda: f.read(blocksize), ""):
+                if len(block) == 0:
+                    break
                 hash.update(block)
         return hash.hexdigest()