fixed THD NO_CUDA (#8539)

diff --git a/torch/lib/THD/CMakeLists.txt b/torch/lib/THD/CMakeLists.txt
index f9826b1..7c2a20e 100644
--- a/torch/lib/THD/CMakeLists.txt
+++ b/torch/lib/THD/CMakeLists.txt
@@ -40,7 +40,6 @@
                         "XCode 8 or newer.")
 ENDIF(NOT HAS_THREAD_LOCAL)
 
-FIND_PACKAGE(NCCL)
 
 FIND_PACKAGE(MPI)
 
@@ -59,6 +58,8 @@
 
     ADD_DEFINITIONS(-DWITH_CUDA=1)
   ENDIF()
+
+  FIND_PACKAGE(NCCL)
 ENDIF()
 
 IF(MPI_FOUND)