BUG: Mantis-1419: FindOpenCV.cmake supports multiarch paths (spotted by Bas Couwenberg <sebastic@debian.org>)

AFAIK, this configuration is not tested on the dashboard. Error before patch :

cmake -DCMAKE_CXX_FLAGS=-std=c++11 -DUSE_SYSTEM_SWIG=OFF -DOTB_WRAP_PYTHON=ON ~/dev/src/otb/SuperBuild/

Call Stack (most recent call first):
  CMake/SuperBuild_Macro.cmake:56 (include)
  CMake/External_otb.cmake:79 (ADDTO_DEPENDENCIES_IF_NOT_SYSTEM)
  CMakeLists.txt:326 (include)

CMake Error at CMake/External_swig.cmake:60 (ADD_SUPERBUILD_CONFIGURE_VAR):
  ADD_SUPERBUILD_CONFIGURE_VAR Macro invoked with incorrect arguments for
  macro named: ADD_SUPERBUILD_CONFIGURE_VAR
Call Stack (most recent call first):
  CMake/SuperBuild_Macro.cmake:56 (include)
  CMake/External_otb.cmake:79 (ADDTO_DEPENDENCIES_IF_NOT_SYSTEM)
  CMakeLists.txt:326 (include)

CMake Error at CMake/External_swig.cmake:61 (ADD_SUPERBUILD_CONFIGURE_VAR):
  ADD_SUPERBUILD_CONFIGURE_VAR Macro invoked with incorrect arguments for
  macro named: ADD_SUPERBUILD_CONFIGURE_VAR
Call Stack (most recent call first):
  CMake/SuperBuild_Macro.cmake:56 (include)
  CMake/External_otb.cmake:79 (ADDTO_DEPENDENCIES_IF_NOT_SYSTEM)
  CMakeLists.txt:326 (include)