image.py: Ensure base image size is an integer

There is a floating point multiplication done of a base image size
and an "overhead factor", which is currently rounded up to the next
integer.  If the multiplication results in a whole number, the value
will still be a float.  When this float is used to generate a shell
script, a buggy script is generated.

Fix this by always forcing to an integer.

(From OE-Core rev: bf74a002b8fa18d94cec93f0341cbe74cc010ca7)

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oe/image.py

@@ -172,6 +172,8 @@ class Image(ImageDepGraph):
 
         if base_size != int(base_size):
             base_size = int(base_size + 1)
+        else:
+            base_size = int(base_size)
 
         base_size += rootfs_alignment - 1
         base_size -= base_size % rootfs_alignment