[Attributor][Fix] Initialize unused but loaded variable

This hopefully un-breaks:
  http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/38333
diff --git a/llvm/lib/Transforms/IPO/Attributor.cpp b/llvm/lib/Transforms/IPO/Attributor.cpp
index 9821d9e..64238ca 100644
--- a/llvm/lib/Transforms/IPO/Attributor.cpp
+++ b/llvm/lib/Transforms/IPO/Attributor.cpp
@@ -4460,7 +4460,7 @@
   ChangeStatus updateImpl(Attributor &A) override {
     bool HasValueBefore = SimplifiedAssociatedValue.hasValue();
 
-    auto VisitValueCB = [&](Value &V, bool, bool Stripped) -> bool {
+    auto VisitValueCB = [&](Value &V, bool &, bool Stripped) -> bool {
       auto &AA = A.getAAFor<AAValueSimplify>(*this, IRPosition::value(V));
       if (!Stripped && this == &AA) {
         // TODO: Look the instruction and check recursively.
@@ -4472,7 +4472,7 @@
       return checkAndUpdate(A, *this, V, SimplifiedAssociatedValue);
     };
 
-    bool Dummy;
+    bool Dummy = false;
     if (!genericValueTraversal<AAValueSimplify, bool>(A, getIRPosition(), *this,
                                                       Dummy, VisitValueCB))
       if (!askSimplifiedValueForAAValueConstantRange(A))