Log Message:
print/ghostscript: Default to ghostscript-agpl

Change SUGGESTED_OPTIONS to ghostscript-agpl, because ghostscript-gpl
is not maintained and has known vulnerabilities, and so that
ghostscript by default results in the version maintained by upstream.

As proposed on pkgsrc-users@, without objection.  Note that this
commit does not change anything related to licensing.

ok pmc