security/libressl-devel: Security update to 2.3.4

• Update to 2.3.4
• Fixes for 4 vulnerabilities

Security: 01d729ca-1143-11e6-b55e-b499baebfeaf
Reviewed by: feld (mentor, ports-secteam)
Approved by: feld (mentor, ports-secteam)
Differential Revision: D6187