Ignore .DS_Store files on mac

Status Job ID Name Coverage
  Test
passed #3576
MultiThreads Linux
clang-c++11-Qt4

00:07:32

passed #3580
MultiThreads Linux
clang-c++11-Qt5

00:09:16

passed #3578
MultiThreads Linux
clang-c++98-Qt4

00:06:43

passed #3582
MultiThreads Linux
clang-c++98-Qt5

00:07:43

passed #3575
Linux
gcc-c++11-Qt4

00:04:46

passed #3579
Linux
gcc-c++11-Qt5

00:04:35

passed #3577
Linux
gcc-c++98-Qt4

00:02:59

passed #3581
Linux
gcc-c++98-Qt5

00:03:44