flush line-clearing on progress stop before post-invoke

All other interactions with std::cout are flushed directly, just in the
stop case we hadn't done it – no problem expect if there is still output
coming after apt is done like in the case of a post-invoke script
producing output.

Closes: 793672

1 files changed, 1 insertions, 0 deletions

diff --git a/apt-pkg/install-progress.cc b/apt-pkg/install-progress.cc
index 14409e301..f1a9f42dc 100644
--- a/apt-pkg/install-progress.cc
+++ b/apt-pkg/install-progress.cc
@@ -333,6 +333,7 @@ void PackageManagerFancy::Stop()
       // override the progress line (sledgehammer)
       static const char* clear_screen_below_cursor = "\033[J";
       std::cout << clear_screen_below_cursor;
+      std::flush(std::cout);
    }
    child_pty = -1;
 }