fixed bug in cmake that prevented proper detection of qt < 5.6

8 jobs for featureQt5.6Support
Status Name Job ID Coverage
  Test
passed clang-c++11-Qt4 #5361
Linux MultiThreads

00:06:57

passed clang-c++11-Qt5 #5365
Linux MultiThreads

00:08:44

passed clang-c++98-Qt4 #5363
Linux MultiThreads

00:06:14

passed clang-c++98-Qt5 #5367
Linux MultiThreads

00:07:32

passed gcc-c++11-Qt4 #5360
Linux

00:03:25

passed gcc-c++11-Qt5 #5364
Linux

00:04:05

passed gcc-c++98-Qt4 #5362
Linux

00:03:47

passed gcc-c++98-Qt5 #5366
Linux

00:03:17