Handle PO files with BOM more elegantly

[dwaynebailey]

Someone tried to upload a PO file translated offline on Verbatim. Source of the issue was a PO file with BOMs, see translate/translate#1640 that discusses the validity of BOMs in PO files (they aren't valid) as well as some options of how to handle this.

We seem to have two options:

1. Sort our toolkit to just drop BOMs
2. Detect and report BOM failures when uploading in Pootle

[jleclanche]

If we're going to "support" those invalid files, let's detect the issue and yank them from the file. This is a case where reporting an error is useless: We know this is invalid, we know why, we know how to fix it, so just do it.

[unho]

I agree with that. Just fix the problem on the fly. No need to report if we can just transparently fix it.

[samuel-lebert-sb]

Hi guys. Old issue but any update on this? Ran into the same issue while implementing Pootle recently.