apply various style suggestions by cppcheck

Some of them modify the ABI, but given that we prepare a big one
already, these few hardly count for much.

Git-Dch: Ignore

1 files changed, 2 insertions, 2 deletions

diff --git a/apt-pkg/install-progress.h b/apt-pkg/install-progress.h
index a4c5daf7f..5da3624c0 100644
--- a/apt-pkg/install-progress.h
+++ b/apt-pkg/install-progress.h
@@ -69,7 +69,7 @@ namespace Progress {
     void WriteToStatusFd(std::string msg);
 
  public:
-    PackageManagerProgressFd(int progress_fd);
+    explicit PackageManagerProgressFd(int progress_fd);
     virtual ~PackageManagerProgressFd();
 
     virtual void StartDpkg();
@@ -100,7 +100,7 @@ namespace Progress {
     void WriteToStatusFd(std::string msg);
 
  public:
-    PackageManagerProgressDeb822Fd(int progress_fd);
+    explicit PackageManagerProgressDeb822Fd(int progress_fd);
     virtual ~PackageManagerProgressDeb822Fd();
 
     virtual void StartDpkg();