MFH: r460962

net/shadowsocks-libev: Update to 3.1.3

Summary of change logs:

• shadowsocks-libev (3.1.3-1)
  • Fix a bug in UDP relay.
• shadowsocks-libev (3.1.2-1)
  • Fix a bug in DNS resolver.
  • Add new TFO API support.
• shadowsocks-libev (3.1.1-1)
  • Fix a security issue in ss-manager. (CVE-2017-15924)

Additional port changes:

• Added LICENSE_FILE
• Sorted GH_TUPLE
• Changed static library to shared library
• Added USE_LDCONFIG
• Added INSTALL_TARGET=install-strip
• Added optional shell completion files for BASH and ZSH

PR: 225442
Submitted by: csosstudy@gmail.com (PORTVERSION line), myself (the rest)
Approved by: ports-secteam (swills), adamw (mentor)
Differential Revision: https://reviews.freebsd.org/D14200