package/boost: stop on the first error during install to staging

-q option is missing in BOOST_INSTALL_STAGING_CMDS,
so the build doesn't stop on the first error.
This help to see what happened.

Signed-off-by: Romain Naour <romain.naour@openwide.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>