cmake DUNE_SYS_HAS_JPEGLIB_H examples

LSTS/dune cmake/Libraries/JPEG.cmake :37 

else(HAVE_LIB_JPEG AND DUNE_SYS_HAS_JPEGLIB_H)

LSTS/dune cmake/Libraries/JPEG.cmake :40 

endif(HAVE_LIB_JPEG AND DUNE_SYS_HAS_JPEGLIB_H)