Add fixed version for CVE-2019-6245

Note for reviewers: Actually possibly the issue was already fixed in
2.5+dfsg1-3 with the inclusion of the 05-fix-recursion-crash.patch
patch. So pinpointing the fixed version needs re-evaluation here.

After 'respin' of a non-dead branch of 2.4's agg version the issue was
fixed in revision 119 and included in 1:2.4-r127+dfsg1-1 but the
05-fix-recursion-crash.patch patch was carried up in each subsequent
versions before that switch.