REFAC: added filesystem to Boost libraries required in OTB

Modules/ThirdParty/Boost/otb-module-init.cmake

@@ -22,9 +22,9 @@ set(Boost_USE_STATIC_LIBS OFF CACHE BOOL "use static libraries from boost")
 
 set(Boost_USE_MULTITHREADED ON CACHE BOOL "use multi-threaded libraries from boost")
 
-find_package (Boost 1.35.0 REQUIRED)
+find_package (Boost 1.35.0 REQUIRED COMPONENTS filesystem)
 if (BUILD_TESTING)
-  find_package (Boost 1.35.0 QUIET COMPONENTS unit_test_framework)
+  find_package (Boost 1.35.0 QUIET COMPONENTS filesystem unit_test_framework)
   if (NOT Boost_UNIT_TEST_FRAMEWORK_FOUND)
     message(STATUS "Boost unit_test_framework not found. Hence otbOGRTests will be skipped")
   else()