Add curly braces to workaround an MSVC bug.

MSVC can't parse this pattern for range-based for loops.

llvm-svn: 222491
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 0560015..9698dbd 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -1178,8 +1178,10 @@
   }
 
   // Check that all instructions have their parent pointers set up correctly.
-  for (auto &I: BB)
+  for (auto &I : BB)
+  {
     Assert(I.getParent() == &BB, "Instruction has bogus parent pointer!");
+  }
 }
 
 void Verifier::visitTerminatorInst(TerminatorInst &I) {