ci: exit setup on any error

-e is preferrable so that we can catch errors in the middle of this
script.
An example is this Travis job [1] that should have errored at the meson
install step rather than go to the build step.

Adding debug mode as it can help post-mortem.

1: https://travis-ci.com/DPDK/dpdk/jobs/223511683

Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Michael Santana <msantana@redhat.com>
Acked-by: Aaron Conole <aconole@redhat.com>

.ci/linux-setup.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/sh -xe
 
 # need to install as 'root' since some of the unit tests won't run without it
 sudo python3 -m pip install --upgrade meson