Return a std::unique_ptr from the IRReader.h functions. NFC.

llvm-svn: 216466
diff --git a/llvm/tools/llvm-extract/llvm-extract.cpp b/llvm/tools/llvm-extract/llvm-extract.cpp
index e369456..8da63fb 100644
--- a/llvm/tools/llvm-extract/llvm-extract.cpp
+++ b/llvm/tools/llvm-extract/llvm-extract.cpp
@@ -101,8 +101,7 @@
 
   // Use lazy loading, since we only care about selected global values.
   SMDiagnostic Err;
-  std::unique_ptr<Module> M;
-  M.reset(getLazyIRFileModule(InputFilename, Err, Context));
+  std::unique_ptr<Module> M = getLazyIRFileModule(InputFilename, Err, Context);
 
   if (!M.get()) {
     Err.print(argv[0], errs());