remove redundent if in CMakeLists

6 jobs for master in 4 minutes and 50 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed clang-c++11 #74116
Linux

00:04:31

passed CoMISo-VS2013-Qt-5.5.1-x64 #74118
VS2013 Qt551

00:01:18

passed CoMISo-VS2017-Qt-5.10.1-x64 #74119
VS2017 IPOPT3129

00:01:13

passed gcc-c++11 #74115
Linux

00:04:24

passed macos-c++11 #74117
Apple

00:04:47

 
  Deploy
passed trigger_build #74120

00:00:02