libsrtp: partially revert previous commit

Signed-off-by: Jiri Slachta <slachta@cesnet.cz>
Disable PKG_CHECK_FORMAT_SECURITY for miax, rtpproxy and sipp

Signed-off-by: Etienne CHAMPETIER <champetier.etienne@gmail.com>
FreeSWITCH:
  1. Fix no FS_WITH_SQLITE3 due to @DEVEL in Config.in
  2. Fix configure error due to no ldns package needed by mod_enum.

Signed-off-by: Mazi Lo <openwrt.mazilo@recursor.net>