Fix shadowed variable in gloo/transport/context.cc

Summary:
Our upcoming compiler upgrade will require us not to have shadowed variables. Such variables have a _high_ bug rate and reduce readability, so we would like to avoid them even if the compiler was not forcing us to do so.

This codemod attempts to fix an instance of a shadowed variable. Please review with care: if it's failed the result will be a silent bug.

**What's a shadowed variable?**

Shadowed variables are variables in an inner scope with the same name as another variable in an outer scope. Having the same name for both variables might be semantically correct, but it can make the code confusing to read! It can also hide subtle bugs.

This diff fixes such an issue by renaming the variable.

 - If you approve of this diff, please use the "Accept & Ship" button :-)

Reviewed By: dmm-fb

Differential Revision: D52582911

fbshipit-source-id: 498a2fab79c04787c136de65e6ac1e9b154640fa

gloo/transport/context.cc

@@ -19,8 +19,8 @@ Context::Context(int rank, int size) : rank(rank), size(size) {
 // Have to provide implementation for pure virtual destructor.
 Context::~Context() {}
 
-std::unique_ptr<transport::Pair>& Context::getPair(int rank) {
-  return pairs_.at(rank);
+std::unique_ptr<transport::Pair>& Context::getPair(int rank_2) {
+  return pairs_.at(rank_2);
 }
 
 void Context::createAndConnectAllPairs(IStore& store) {