dump-file limits to 2gb

With such config stream.mp3 grows to 2147483647 bytes (2GB-1byte) and stops. Server proceed without problems.

    <mount> 
        <mount-name>/stream</mount-name> 
        <dump-file>/home/user/dump/stream.mp3</dump-file> 
    </mount>

icecast 2.3.1 gentoo linux pentium4