osbuild-mpp: fix float correction

I mistakenly thought the .strip('.0') would strip off just '.0` but
in reality it strips off all instances of `.` or `0` on the end so
'4075520.0'.strip('.0') => '407552', which is clearly wrong.

This is a fixup for 5207e92.

tools/osbuild-mpp

@@ -1288,7 +1288,7 @@ class ManifestFile:
                 # some math that ended up converting the value to a
                 # float. Just trim it off in that case.
                 if res.endswith('.0'):
-                    res = res.strip('.0')
+                    res = res[0:-2]
                 res = int(res)
             elif res_type == "json":
                 res = json.loads(res)