BmapCreate: make sha256 to be the default

Change-Id: I9d788371cfcc8a6c45ac7c443421c757058a12c6
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>

Author: dedekind

bmaptools/BmapCreate.py

@@ -112,7 +112,7 @@ class BmapCreate:
     the FIEMAP ioctl to generate the bmap.
     """
 
-    def __init__(self, image, bmap, chksum_type="sha1"):
+    def __init__(self, image, bmap, chksum_type="sha256"):
         """
         Initialize a class instance:
         * image  - full path or a file-like object of the image to create bmap