[fix] utils/lib.sh: prefix_stdout show cursor (ANSI escape \e[?25h)

Some piped commands hide the cursor, show cursory when the stream ends.

Most often this is a bug of the command which piped.  The command should not
hide the cursor when it writes to a pipe.  I have seen this bug with the package
manager (pacman) from ArchLinux.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>