Fix a compiler error on MSVC (variable name 'E' clash).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@49727 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/GRSimpleVals.cpp b/lib/Analysis/GRSimpleVals.cpp
index b37ccf5..dabae43 100644
--- a/lib/Analysis/GRSimpleVals.cpp
+++ b/lib/Analysis/GRSimpleVals.cpp
@@ -228,7 +228,7 @@
     GRExprEngine& Eng = BR.getEngine();
     
     for (GRExprEngine::UndefReceiversTy::iterator I=Eng.undef_receivers_begin(),
-         E = Eng.undef_receivers_end(); I!=E; ++I) {
+         End = Eng.undef_receivers_end(); I!=End; ++I) {
           
       // Generate a report for this bug.
       RangedBugReport report(*this, *I);