Update for LLVM API change.

llvm-svn: 216603
diff --git a/lldb/source/Expression/ClangExpressionParser.cpp b/lldb/source/Expression/ClangExpressionParser.cpp
index a204a1e..e235ea5 100644
--- a/lldb/source/Expression/ClangExpressionParser.cpp
+++ b/lldb/source/Expression/ClangExpressionParser.cpp
@@ -333,8 +333,8 @@
 
     if (!created_main_file)
     {
-        MemoryBuffer *memory_buffer = MemoryBuffer::getMemBufferCopy(expr_text, __FUNCTION__);
-        SourceMgr.setMainFileID(SourceMgr.createFileID(memory_buffer));
+        std::unique_ptr<MemoryBuffer> memory_buffer = MemoryBuffer::getMemBufferCopy(expr_text, __FUNCTION__);
+        SourceMgr.setMainFileID(SourceMgr.createFileID(memory_buffer.release()));
     }
 
     diag_buf->BeginSourceFile(m_compiler->getLangOpts(), &m_compiler->getPreprocessor());