SW-609: Make CMake look for libboost_python3 if building with python3 dependency

CMake/FindBoost.cmake

@@ -63,18 +63,9 @@ if("${Boost_FIND_COMPONENTS}" MATCHES "python")
   find_package(Python)
   if(PYTHON_FOUND)
     if(PYTHON_VERSION_MAJOR GREATER 2)
-      # TODO: add support for CentOS7 here (name should be python3 there)
-      if(APPLE)
-        # On apple (homebrew), boost-python for python 3 is called boost-python3
-        string(REPLACE "python" "python3"
-               Boost_FIND_COMPONENTS "${Boost_FIND_COMPONENTS}")
-      else(APPLE)
-        # On ubuntu, boost-python for python 3 is called e.g. boost_python-py35
-        string(REPLACE "python"
-                       "python-py${PYTHON_VERSION_MAJOR}${PYTHON_VERSION_MINOR}"
-               Boost_FIND_COMPONENTS "${Boost_FIND_COMPONENTS}")
-      endif(APPLE)
-  endif(PYTHON_VERSION_MAJOR GREATER 2)
+      string(REPLACE "python" "python3"
+             Boost_FIND_COMPONENTS "${Boost_FIND_COMPONENTS}")
+    endif(PYTHON_VERSION_MAJOR GREATER 2)
   else(PYTHON_FOUND)
     message(SEND_ERROR "boost-python was requested but python was not found.")
   endif(PYTHON_FOUND)