BUG/MINOR: acl: warn if "_sub" derivative used with an explicit match

BUG/MINOR: acl: warn if "_sub" derivative used with an explicit match

Recently, a new warning is displayed when an ACL derivative match method
is override with another '-m' method. This is implemented via the
following patch :

  6ea50ba462692d6dcf301081f23cab3e0f6086e4
  MINOR: acl; Warn when matching method based on a suffix is overwritten

However, this warning was not reported when "_sub" suffix was specified.
Fix this by adding PAT_MATCH_SUB in the warning comparison.

No backport needed except if above commit is.