Log Message:
p5-libwww: update to 6.27.

6.27      2017-09-21
    - Switch to Getopt::Long in lwp-download (GH #262)
    - Fix lwp-request -C (GH #261)
    - Hide LWP::Protocol::http::Socket, LWP::Protocol::http::SocketMethods and
      LWP::Debug::TraceHTTP::Socket from PAUSE
    - Add tests for the "get" & "head" functions (GH #252)
    - Update lwpcook.pod (GH #256)
    - Handle undefined values in ->credentials (GH #157)
    - Fix lwp-mirror options checks.
    - Update bin/ scripts to use $LWP::VERSION instead of ->Version()
    - Improve lwp-download --help (GH #262)