getpatch: Do not error out if a patch has a custom encoding.

[rakuco]

Summary

Some patches, such as one of the ones sent in 189248, has a custom encoding, so the details page says "foo.diff (text/plain; charset=windows-1250)" instead of just "foo.diff (text/plain)". This made _extract_patchs_name() fail without any further explanation.

Make the regexp more flexible by accepting a charset entry after the mime-type in the details.

[rakuco]

Tools/scripts/getpatch

123

Another possibility is matching \(text/plain instead of \(text/plain\) to accept anything coming after that.

[sbz]

Committed in r362667 . Thanks!