acl-plugin: "show acl-plugin acl" ACE# is truncated to 4 digits in output

I was expecting "%4d" format string to exhibit the same behavior as
the one in C standard library, but rather than specifying _minimal_
width and expanding as necessary, it actually truncates the output.

Changing that to "%9d" should take care of pushing this surprising
difference in behavior into the domain of impossible.

Change-Id: Ia687137ca765bf9c1575af998ff11314010e81ad
Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com>