Fix for lifetime bug in retrying.

Summary: Late change in D9175807 removed necessary temporaries. This caused a lifetime management problem for GCC.

Reviewed By: Orvid

Differential Revision: D9227937

fbshipit-source-id: d5fea8a98855c6302189a7dee8cd5862d13a63a3

folly/futures/Retrying.h

@@ -83,8 +83,8 @@ template <class Policy, class FF, class Prom>
 void retryingImpl(size_t k, Policy&& p, FF&& ff, Prom prom) {
   using F = invoke_result_t<FF, size_t>;
   using T = typename F::value_type;
-  makeFutureWith([&] { return ff(k++); })
-      .then([k,
+  auto f = makeFutureWith([&] { return ff(k++); });
+  f.then([k,
           prom = std::move(prom),
           pm = std::forward<Policy>(p),
           ffm = std::forward<FF>(ff)](Try<T>&& t) mutable {
@@ -93,8 +93,8 @@ void retryingImpl(size_t k, Policy&& p, FF&& ff, Prom prom) {
       return;
     }
     auto& x = t.exception();
-        makeFutureWith([&] { return pm(k, x); })
-            .then([k,
+    auto q = makeFutureWith([&] { return pm(k, x); });
+    q.then([k,
             prom = std::move(prom),
             xm = std::move(x),
             pm = std::move(pm),