support/apply-patches: re-instate set -e

support/apply-patches: re-instate set -e

As reported by Sébastien Szymanski [1], the apply-patches script
doesn't stop if a tar command can't extract an archive.

Use "set -e" to exit immediately if a command return an error.

Be sure to ignore any expected error: when we check if a patch to be
applied has the same basename as an already applied patch, the grep
would fail when no such patch was already applied. We should not fail
in this case.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
Cc: Romain Naour <romain.naour@openwide.fr>
Reviewed-by: Romain Naour <romain.naour@gmail.com>
Tested-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>