Drop intermediate list of files from log reading

We are saving a temporary variable in a ton of places for the lifetime
of the program.  Inline it so we can change the return type.

Change-Id: If8d90ffd07806644aceed4c44087e5fd206c8df9
Signed-off-by: James Kuszmaul <james.kuszmaul@bluerivertech.com>
diff --git a/y2020/vision/viewer_replay.cc b/y2020/vision/viewer_replay.cc
index a818859..03777bc 100644
--- a/y2020/vision/viewer_replay.cc
+++ b/y2020/vision/viewer_replay.cc
@@ -17,11 +17,9 @@
 namespace {
 
 void ViewerMain(int argc, char *argv[]) {
-  std::vector<std::string> unsorted_logfiles =
-      aos::logger::FindLogs(argc, argv);
-
   // open logfiles
-  aos::logger::LogReader reader(aos::logger::SortParts(unsorted_logfiles));
+  aos::logger::LogReader reader(
+      aos::logger::SortParts(aos::logger::FindLogs(argc, argv)));
   reader.Register();
   const aos::Node *node = nullptr;
   if (aos::configuration::MultiNode(reader.configuration())) {