Fixes for upstream bug#3868, upstream bug#4230 (CVE-2016-3125)
- Fix for CVE-2016-3125: usage of 1024 bit DH key even with manual parameters
set (http://bugs.proftpd.org/show_bug.cgi?id=4230)
- Also fixed related issue where only first DH param in TLSDHParamFile is used,
regardless of requested keylength
(http://bugs.proftpd.org/show_bug.cgi?id=3868)