strace: show test suite log on failure

If the tests fail, dump the log so we can see the failures.

(From OE-Core rev: 3154a65039831b1e041217707fdd6ca042f588fb)

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/strace/strace/run-ptest

@@ -1,6 +1,15 @@
 #!/bin/sh
+
+set -u
+
 export TIMEOUT_DURATION=240
 chown nobody tests
 chown nobody tests/*
 chown nobody ../ptest
+
 su nobody -c "make -B -C tests -k test-suite.log"
+res=$?
+if [ $res -ne 0 ]; then
+    cat tests/test-suite.log
+fi
+exit $res