tests: Increase verbosity in *_test.in checks

In this case it does not hurt to increase bash execution verbosity so
we can get more insight in case of issues.

Signed-off-by: Leo Sandoval <lsandova@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

tests/tar_test.in

@@ -1,6 +1,6 @@
 #!@BUILD_SHEBANG@
 
-set -e
+set -ex
 
 if ! which tar >/dev/null 2>&1; then
    echo "tar not installed; cannot test tar."