[C++, Build] fixed CMake variable for clang-tidy
[C++, Build] fixed CMake variable for clang-tidy

Change-Id: Ic97dd8c6a54ebac283f8a57e7299aefa36380a8f

bmwcarit/joynr,bmwcarit/joynr,clive-jevons/joynr,bmwcarit/joynr,clive-jevons/joynr,clive-jevons/joynr,bmwcarit/joynr,bmwcarit/joynr,clive-jevons/joynr,bmwcarit/joynr,bmwcarit/joynr,clive-jevons/joynr,bmwcarit/joynr,bmwcarit/joynr,clive-jevons/joynr