qtuio: add error handling to for loop

Also remove unneeded sub-shell usage in the build and installation
steps. It is kept for the configure step as it is actually useful, and
works fine because "|| exit 1" is outside the sub-shell.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>