BundleFile: fix exception on file.save("original")

[astiob]

Regression in commit 9232cdd (release 1.9.21), which renamed _data_flags to dataflags.

[astiob]

On a slightly related note (I’d open a separate GitHub issue, but it isn’t exactly a bug), save_fs should maybe throw if the data_flags argument includes the encryption flag, because (as far as I can tell) UnityPy doesn’t implement encryption upon saving. But this isn’t entirely trivial to implement because the argument may be passed as a raw integer, so you’d need to duplicate the version-dependent logic from read_fs just to figure out what the integer means.

[K0lb3]

Thanks for noticing and fixing the issue.
And you're right, it should error in case it's supposed to store an encrypted bundle.