Use the internal ckf by default.

This MR should fix the CI issue in MR !6 (merged).

cmake/CEPCSWDependencies.cmake

@@ -36,4 +36,11 @@ find_package(PandoraSDK REQUIRED)
 find_package(podio REQUIRED)
 find_package(ROOT COMPONENTS EG Graf Graf3d Gpad MathCore Net RIO Tree TreePlayer REQUIRED)
 find_package(GenFit)
-find_package(BelleIICKF)
+
+if (CEPCSW_USE_SYSTEM_CKF_BELLE)
+  message("Try to use an existing installation of CKF BELLE")
+  find_package(BelleIICKF)
+else()
+  message("Try to use an internal installation of CKF BELLE")
+  include("${CMAKE_CURRENT_LIST_DIR}/internal_ckf.cmake")
+endif()