CMake: don't create directories lib/bornagain, lib/exec

cmake/BornAgain/Directories.cmake

@@ -47,8 +47,6 @@ set(TEST_OUTPUT_DIR_STD         ${TEST_OUTPUT_DIR}/Std)
 configure_file("${CONFIGURABLES_DIR}/auto_README.in.md" "${CMAKE_SOURCE_DIR}/auto/README.md" @ONLY)
 
 file(MAKE_DIRECTORY ${CMAKE_LIBRARY_OUTPUT_DIRECTORY})
-file(MAKE_DIRECTORY ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/bornagain)
-file(MAKE_DIRECTORY ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/exec)
 file(MAKE_DIRECTORY ${CMAKE_RUNTIME_OUTPUT_DIRECTORY})
 file(MAKE_DIRECTORY ${BUILD_VAR_DIR})
 file(MAKE_DIRECTORY ${BUILD_INC_DIR})