title: building OpenCV as deb package: CPackDeb: file utility is not available
body: <p>I'm building OpenCV 4.1 as a deb package on Ubuntu 18.04. After success in building libraries. I'm calling <code>make package</code> and getting the following error:</p>
  
  <p><code>CPack: Create package
  CMake Error at /usr/share/cmake-3.10/Modules/CPackDeb.cmake:622 (message):
    CPackDeb: file utility is not available.  CPACK_DEBIAN_PACKAGE_SHLIBDEPS
    and CPACK_DEBIAN_PACKAGE_GENERATE_SHLIBS options are not available.
  Call Stack (most recent call first):
    /usr/share/cmake-3.10/Modules/CPackDeb.cmake:1119 (cpack_deb_prepare_package_vars)</code></p>
  
  <p>Does anybody have any ideas on how to fix it?</p>