If a browser claims a file's content type is application/octet-stream,

get a second opinion by asking file --mime-type. This helps with some

browsers or server setups where that useless mimetype is being used,

preventing some files from being reviewable.

Faked the application/octet-stream mimetype on a file (by setting it just

before this conditional) and saw that the uploaded .c file was reviewable.

Before the conditional fix, it was uploaded with the application/octet-stream

mimetype.