[cmake] Use underscore name only for python.

CMakeLists.txt

@@ -34,7 +34,6 @@ INCLUDE(cmake/python.cmake)
 COMPUTE_PROJECT_ARGS(PROJECT_ARGS LANGUAGES CXX C)
 PROJECT(${PROJECT_NAME} ${PROJECT_ARGS})
 
-STRING(REGEX REPLACE "-" "_" PROJECT_NAME_UNDERSCORE ${PROJECT_NAME})
 IF(INITIALIZE_WITH_NAN)
   MESSAGE(STATUS "Initialize with NaN all the Eigen entries.")
   ADD_DEFINITIONS(-DEIGEN_INITIALIZE_MATRICES_BY_NAN)
@@ -45,6 +44,7 @@ SET(BOOST_COMPONENTS thread filesystem program_options unit_test_framework syste
 
 IF(BUILD_PYTHON_INTERFACE)
   FINDPYTHON()
+  STRING(REGEX REPLACE "-" "_" PROJECT_NAME_UNDERSCORE ${PROJECT_NAME})  
   SET(PY_NAME ${PROJECT_NAME_UNDERSCORE})
   ADD_PROJECT_DEPENDENCY(dynamic-graph-python REQUIRED
     PKG_CONFIG_REQUIRES dynamic-graph-python)
@@ -200,5 +200,5 @@ ENDIF(BUILD_TESTING)
 
 PKG_CONFIG_APPEND_LIBS(${PROJECT_NAME})
 IF(NOT INSTALL_PYTHON_INTERFACE_ONLY)
-  INSTALL(FILES package.xml DESTINATION share/${PROJECT_NAME_UNDERSCORE})
+  INSTALL(FILES package.xml DESTINATION share/${PROJECT_NAME})
 ENDIF(NOT INSTALL_PYTHON_INTERFACE_ONLY)