Remove erroneous prefix bits from BIP-0039 french wordlist

[cornfeedhobo]

This PR seeks to remove a strange prefix found in the french wordlist.

This can be confirmed with hexdump -C -n 8 bip-0039/french.txt.

00000000  ef bb bf 61 62 61 69 73                           |...abais|

The first 8 bytes should be the word abaisser.

00000000  61 62 61 69 73 73 65 72                           |abaisser|

[iancoleman]

See #537

That's the UTF8 BOM marker (3 bytes EF BB BF). You should not remove that, as it will disable automatic encoding recognition for some apps.

And further discussion in #622

[cornfeedhobo]

@iamsamwood thanks. I'm going to close this and follow #622.