cleanup: Fix warnings found by cppcheck

Fix various warnings found by cppcheck.

Signed-off-by: Lei YU <yulei.sh@bytedance.com>
Change-Id: I4db2319f5890d7aa73c8f418f610a6cba338ce24
diff --git a/image_manager.cpp b/image_manager.cpp
index a9a5a69..922575b 100644
--- a/image_manager.cpp
+++ b/image_manager.cpp
@@ -42,7 +42,7 @@
 {
     fs::path path;
 
-    RemovablePath(const fs::path& path) : path(path)
+    explicit RemovablePath(const fs::path& path) : path(path)
     {}
     ~RemovablePath()
     {