Handle redeclarations of catch variables in catch blocks.

Fix to regression caused by r167650, caught by Richard Smith in code review.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@167653 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/IdentifierResolver.cpp b/lib/Sema/IdentifierResolver.cpp
index 50413c3..0093915 100644
--- a/lib/Sema/IdentifierResolver.cpp
+++ b/lib/Sema/IdentifierResolver.cpp
@@ -138,8 +138,11 @@
       if (S->getFlags() & Scope::FnTryScope)
         return S->getParent()->isDeclScope(D);
       if (S->getParent()->getFlags() & Scope::ControlScope) {
-        if (S->getParent()->getFlags() & Scope::FnCatchScope)
+        if (S->getParent()->getFlags() & Scope::FnCatchScope) {
           S = S->getParent();
+          if (S->isDeclScope(D))
+            return true;
+        }
         return S->getParent()->isDeclScope(D);
       }
     }