Fixed a build problem dueo to changes in the
way ownership of memory buffers is handled in
clang's SourceManager.

llvm-svn: 216810
diff --git a/lldb/source/Expression/ClangExpressionParser.cpp b/lldb/source/Expression/ClangExpressionParser.cpp
index e235ea5..f32ca3a 100644
--- a/lldb/source/Expression/ClangExpressionParser.cpp
+++ b/lldb/source/Expression/ClangExpressionParser.cpp
@@ -334,7 +334,7 @@
     if (!created_main_file)
     {
         std::unique_ptr<MemoryBuffer> memory_buffer = MemoryBuffer::getMemBufferCopy(expr_text, __FUNCTION__);
-        SourceMgr.setMainFileID(SourceMgr.createFileID(memory_buffer.release()));
+        SourceMgr.setMainFileID(SourceMgr.createFileID(std::move(memory_buffer)));
     }
 
     diag_buf->BeginSourceFile(m_compiler->getLangOpts(), &m_compiler->getPreprocessor());