Update sysutils/py-salt to 2017.7.1

• Includes fix for security vulnerability CVE-2017-12791
• Include patch to fix bug in the freebsdservice module [1]
• Add TCP transport option
• Clarify the port options for transports only install the runtime dependencies
• Add note to pkg-message explaining how to change to non-default transports
• Change supported python releases to exclude 2.6 and allow python3 [2]
• Only depend on py-enum34 if python version is < 3.4 (included in python >= 3.4)
• Reorder Makefile to move OPTIONS after USES/USE/standard variables [3]
• Ensure Makefile lists are sorted alphabetically

[1] https://github.com/saltstack/salt/issues/36675#issuecomment-323586323
[2] https://docs.saltstack.com/en/latest/topics/releases/2017.7.0.html#python-3
[3] https://www.freebsd.org/doc/en/books/porters-handbook/porting-order.html

Changes this release:

https://docs.saltstack.com/en/latest/topics/releases/2017.7.0.html
https://docs.saltstack.com/en/latest/topics/releases/2017.7.1.html

PR: 220869
Reported by: Christer Edwards <christer.edwards@gmail.com> (maintainer)
Approved by: Christer Edwards <christer.edwards@gmail.com> (maintainer)
Security: CVE-2017-12791
Security: https://vuxml.freebsd.org/freebsd/3531141d-a708-477c-954a-2a0549e49ca9.html