sysutils/py-salt: update 2015.5.3 -> 2015.5.4 [1], add salt_api rc script [2]

PR: 202417 [1]
PR: 202042 [2]
Submitted by: Christer Edwards <christer.edwards@gmail.com> (maintainer) [1]
Submitted by: xenophon+fbsdports@irtnog.org [2]
Approved by: maintainer [2], feld (mentor)