Fix progress bar flicker with -L

This was caused by -L calling setLogFormat() again, which caused the
creation of a new progress bar without destroying the old one. So we
had two progress bars clobbering each other.

We should change 'logger' to be a smart pointer, but I'll do that in a
future PR.

Fixes #6931.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/libmain/progress-bar.hh b/src/libmain/progress-bar.hh
index 7f0dafecf..3a76f8448 100644
--- a/src/libmain/progress-bar.hh
+++ b/src/libmain/progress-bar.hh
@@ -4,9 +4,9 @@
 
 namespace nix {
 
-Logger * makeProgressBar(bool printBuildLogs = false);
+Logger * makeProgressBar();
 
-void startProgressBar(bool printBuildLogs = false);
+void startProgressBar();
 
 void stopProgressBar();