test: set soft ulimit

when the current soft limit is higher than the new value, ulimit fails
to set the hard limit as (tested on Rawhide):

[root@rawhide ~]# ulimit -n -H 1048575
-bash: ulimit: open files: cannot modify limit: Invalid argument

to avoid the problem, set also the soft limit:

[root@rawhide ~]# ulimit -n -H
12345678
[root@rawhide ~]# ulimit -n -H 1048575
-bash: ulimit: open files: cannot modify limit: Invalid argument
[root@rawhide ~]# ulimit -n -SH 1048575
[root@rawhide ~]# ulimit -n -H
1048575

commit 71d5ee0e04 introduced the issue.

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

test/system/030-run.bats

@@ -1315,7 +1315,7 @@ EOF
     default_value=$output
 
     # Set the current ulimit smaller than the default value
-    ulimit -n -H $((default_value - 1))
+    ulimit -n -SH $((default_value - 1))
 
     run_podman run --rm $IMAGE sh -c 'ulimit -n -H'