style(3p/nix): Add braces around single-line conditionals r/771

These were not caught by the previous clang-tidy invocation, but were
instead sorted out using amber[0] as such:

    ambr --regex 'if (\(.+\))\s([a-z].*;)' 'if $1 { $2 }'

[0]: https://github.com/dalance/amber

1 files changed, 3 insertions, 1 deletions

diff --git a/third_party/nix/src/nix-copy-closure/nix-copy-closure.cc b/third_party/nix/src/nix-copy-closure/nix-copy-closure.cc
index 46b326a918..2ec6a02136 100644
--- a/third_party/nix/src/nix-copy-closure/nix-copy-closure.cc
+++ b/third_party/nix/src/nix-copy-closure/nix-copy-closure.cc
@@ -49,7 +49,9 @@ static int _main(int argc, char** argv) {
 
     initPlugins();
 
-    if (sshHost.empty()) throw UsageError("no host name specified");
+    if (sshHost.empty()) {
+      throw UsageError("no host name specified");
+    }
 
     auto remoteUri = "ssh://" + sshHost + (gzip ? "?compress=true" : "");
     auto to = toMode ? openStore(remoteUri) : openStore();