[autotest] tst_qfont fails on OSX 10.8

This test is always failing on macx-clang_developer-build_OSX_10.8 stage.
See http://testresults.qt-project.org/ci//Qt5_stable_Integration/build_00391/macx-clang_developer-build_OSX_10.8/log.txt.gz

FAIL! : tst_QFont::defaultFamily(serif) 'isAcceptable' returned FALSE. (Font family 'Lucida Grande' is not one of the following accaptable results:
Times New Roman
Times
serif)
Loc: [tst_qfont.cpp(688)]
FAIL! : tst_QFont::defaultFamily(monospace) 'isAcceptable' returned FALSE. (Font family 'Lucida Grande' is not one of the following accaptable results:
Courier New
Monaco
monospace)
Loc: [tst_qfont.cpp(688)]
FAIL! : tst_QFont::defaultFamily(cursive) 'isAcceptable' returned FALSE. (Font family 'Lucida Grande' is not one of the following accaptable results:
Comic Sans MS
Apple Chancery
cursive)
Loc: [tst_qfont.cpp(688)]
FAIL! : tst_QFont::defaultFamily(fantasy) 'isAcceptable' returned FALSE. (Font family 'Lucida Grande' is not one of the following accaptable results:
Impact
Zapfino
fantasy)
Loc: [tst_qfont.cpp(688)]