[GTK] Programs/WebKit2APITests/TestWebKitSettings unit test is failing
https://bugs.webkit.org/show_bug.cgi?id=124924

Reviewed by Carlos Garcia Campos.

'Chrome'/'Chromium' substrings were removed from the user agent string in r159572, meaning the unit
test shouldn't check for those two substrings anymore. Instead, 'Safari' (as until now) and 'AppleWebKit'
substrings should be checked for.

* UIProcess/API/gtk/tests/TestWebKitSettings.cpp:
(testWebKitSettingsUserAgent):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@159811 268f45cc-cd09-0410-ab3c-d52691b4dbfc