[CMake] Put libcxx-specific module directories to the front of CMAKE_MODULE_PATH.

Otherwise if libcxx is built as an LLVM external project (after r191624),
"include(config-ix)" will include config-ix.cmake from LLVM, not from libcxx,
which will result in misconfigured build tree.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@191657 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9723d26..b8f9a03 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,9 +14,9 @@
 
 # Add path for custom modules
 set(CMAKE_MODULE_PATH
-  ${CMAKE_MODULE_PATH}
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
+  ${CMAKE_MODULE_PATH}
   )
 
 # Require out of source build.