Include llvm::Optional in clang/Basic/LLVM.h

Post-commit CR feedback from Jordan Rose regarding r175594.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175679 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/StaticAnalyzer/Checkers/AttrNonNullChecker.cpp b/lib/StaticAnalyzer/Checkers/AttrNonNullChecker.cpp
index 6185a8e..de5e6dc 100644
--- a/lib/StaticAnalyzer/Checkers/AttrNonNullChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/AttrNonNullChecker.cpp
@@ -51,7 +51,7 @@
       continue;
 
     SVal V = Call.getArgSVal(idx);
-    llvm::Optional<DefinedSVal> DV = V.getAs<DefinedSVal>();
+    Optional<DefinedSVal> DV = V.getAs<DefinedSVal>();
 
     // If the value is unknown or undefined, we can't perform this check.
     if (!DV)
@@ -69,7 +69,7 @@
       if (!UT || !UT->getDecl()->hasAttr<TransparentUnionAttr>())
         continue;
 
-      if (llvm::Optional<nonloc::CompoundVal> CSV =
+      if (Optional<nonloc::CompoundVal> CSV =
               DV->getAs<nonloc::CompoundVal>()) {
         nonloc::CompoundVal::iterator CSV_I = CSV->begin();
         assert(CSV_I != CSV->end());