Revert special handling not needed on Gentoo.
https://bugs.gentoo.org/show_bug.cgi?id=608330

Index: camera_calibration_parsers/CMakeLists.txt
===================================================================
--- camera_calibration_parsers.orig/CMakeLists.txt
+++ camera_calibration_parsers/CMakeLists.txt
@@ -4,11 +4,7 @@ project(camera_calibration_parsers)
 find_package(catkin REQUIRED sensor_msgs rosconsole roscpp roscpp_serialization)
 
 find_package(PythonLibs REQUIRED)
-if(PYTHONLIBS_VERSION_STRING VERSION_LESS 3)
-  find_package(Boost REQUIRED COMPONENTS filesystem python)
-else()
-  find_package(Boost REQUIRED COMPONENTS filesystem python3)
-endif()
+find_package(Boost REQUIRED COMPONENTS filesystem python${PYTHON_VERSION_MAJOR}${PYTHON_VERSION_MINOR})
 include_directories(include ${catkin_INCLUDE_DIRS} ${Boost_INCLUDE_DIRS} ${PYTHON_INCLUDE_DIRS})
 
 catkin_python_setup()