refactor(3p/nix): Apply clang-tidy's readability-* fixes r/788

This applies the readability fixes listed here:

https://clang.llvm.org/extra/clang-tidy/checks/list.html

1 files changed, 1 insertions, 1 deletions

diff --git a/third_party/nix/src/nix-collect-garbage/nix-collect-garbage.cc b/third_party/nix/src/nix-collect-garbage/nix-collect-garbage.cc
index dee803ada3..c3ff068887 100644
--- a/third_party/nix/src/nix-collect-garbage/nix-collect-garbage.cc
+++ b/third_party/nix/src/nix-collect-garbage/nix-collect-garbage.cc
@@ -42,7 +42,7 @@ void removeOldGenerations(std::string dir) {
       }
       if (link.find("link") != string::npos) {
         LOG(INFO) << "removing old generations of profile " << path;
-        if (deleteOlderThan != "") {
+        if (!deleteOlderThan.empty()) {
           deleteGenerationsOlderThan(path, deleteOlderThan, dryRun);
         } else {
           deleteOldGenerations(path, dryRun);