switch experimental::fs to std::fs

std::filesystem was added to C++17 and is well supported now.  Remove
the older std::experimental::filesystem usage.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ie960192eaefec8e0e0b4290929a2fa7bb7710c7a
diff --git a/CMakeLists.txt b/CMakeLists.txt
index f6a9801..c6c34ad 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -72,7 +72,7 @@
 link_directories(${DBUSINTERFACE_LIBRARY_DIRS})
 
 add_executable(${PROJECT_NAME} ${SRC_FILES} )
-target_link_libraries(${PROJECT_NAME} "${SDBUSPLUSPLUS_LIBRARIES} -lphosphor_dbus  -lstdc++fs")
+target_link_libraries(${PROJECT_NAME} "${SDBUSPLUSPLUS_LIBRARIES} -lphosphor_dbus")
 
 add_executable(button-handler ${HANDLER_SRC_FILES})
 target_link_libraries(button-handler "${SDBUSPLUSPLUS_LIBRARIES} -lphosphor_dbus")