[Distributed] remove a few warnings

Author: ktoso

lib/SILGen/SILGenDistributed.cpp

@@ -43,8 +43,6 @@ using namespace Lowering;
 ///          or the subsequent cast to VarDecl failed.
 static VarDecl* lookupProperty(NominalTypeDecl *decl, DeclName name) {
   assert(decl && "decl was null");
-  auto &C = decl->getASTContext();
-  
   if (auto clazz = dyn_cast<ClassDecl>(decl)) {
     auto refs = decl->lookupDirect(name);
     if (refs.size() != 1)

lib/Sema/CodeSynthesisDistributedActor.cpp

@@ -564,7 +564,6 @@ addDistributedActorCodableConformance(
   assert(proto->isSpecificProtocol(swift::KnownProtocolKind::Decodable) ||
          proto->isSpecificProtocol(swift::KnownProtocolKind::Encodable));
   auto &C = actor->getASTContext();
-  auto DC = actor->getDeclContext();
   auto module = actor->getParentModule();
 
   // === Only Distributed actors can gain this implicit conformance