Update SassScriptFunctions.php

[LukasMeine]

Fixes the problem described on this open issue: #134

[joejoseph00]

The Travis CI build failed, see details below

1) PHPSass_TestCase::testHSLFunction

Result for hsl-functions.scss did not match comparison file

Failed asserting that two strings are equal.

--- Expected

+++ Actual

@@ @@

-'#hsl{background:#010101background:rgba(1,1,1,0.5)background:32.975degbackground:100%background:47.451%background:#f28500background:#f58600background:#ef8400background:#f28500background:#f18501background:grayscale(#f28500)background:#006df2background:#0d7aff}'

+'#hsl{background:#010101background:rgba(1,1,1,0.5)background:32.975degbackground:100%background:47.451%background:#f28500background:#f58600background:#ef8400background:#f28500background:#f18501background:#797979background:#006df2background:#0d7aff}'

/home/travis/build/richthegeek/phpsass/tests/phpSassTest.php:91

/home/travis/build/richthegeek/phpsass/tests/phpSassTest.php:200

FAILURES!

Tests: 59, Assertions: 60, Failures: 1, Incomplete: 1.

[joejoseph00]

#797979background
comes out instead of
grayscale(#f28500)background