tests/should-fail: Verify exit code 1

Some of these runs were exiting with SIGSEGV but because we
were just checking that the command failed, we masked that error...
Fix the test code here to verify that the process exited with code 1.

Signed-off-by: Colin Walters <walters@verbum.org>

Author: cgwalters

tests/test-should-fail.sh

@@ -7,8 +7,14 @@ shift
 tmpd=$(mktemp -d -t lcfs-test.XXXXXX)
 trap 'rm -rf -- "$tmpd"' EXIT
 for f in $@; do
-    if $bindir/mkcomposefs --from-file $f $tmpd/out.cfs &>/dev/null; then
+    rc=0
+    $bindir/mkcomposefs --from-file $f $tmpd/out.cfs >/dev/null 2>$tmpd/err.txt || rc=$?
+    if test $rc == 0; then
         fatal "Test case $f should have failed"
     fi
+    if test $rc != 1; then
+        cat $tmpd/err.txt
+        fatal "Test case $f exited with code $rc, not 1"
+    fi
     echo "ok $f"
 done