Refactor: Fix issues found by cppcheck

Resolve several issues found by cppcheck:

    [msl_verify.hpp:28]: (style) Class 'MinimumShipLevel' has a constructor with 1 argument that is not explicit.
    [ubi/watch.hpp:21]: (warning) Assignment of function parameter has no effect outside the function. Did you forget dereferencing it?
    [item_updater_main.cpp:22] -> [item_updater_main.cpp:49]: (style) Local variable rc shadows outer symbol
    [serialize.cpp:19]: (performance) Function parameter 'versionId' should be passed by const reference.
    [ubi/watch.hpp:43]: (style) Struct 'CustomFd' has a constructor with 1 argument that is not explicit.
    [serialize.cpp:52]: (performance) Function parameter 'versionId' should be passed by const reference.
    [serialize.cpp:116]: (performance) Function parameter 'versionId' should be passed by const reference.
    [activation.cpp:115] -> [activation.cpp:152]: (style) Local variable mapperResponseMsg shadows outer symbol
    [version.hpp:114]: (performance) Variable 'eraseCallback' is assigned in constructor body. Consider performing initialization in initialization list.
    [image_verify.hpp:53]: (style) Struct 'CustomFd' has a constructor with 1 argument that is not explicit.
    [ubi/item_updater_ubi.cpp:192]: (performance) Function parameter 'versionId' should be passed by const reference.
    [ubi/item_updater_ubi.cpp:203]: (performance) Function parameter 'versionId' should be passed by const reference.

Tested: Verify the code compiles and cppcheck does not report the above
        issues.

Change-Id: I096392a2a7a283fe198c9c29185125e61295e10f
Signed-off-by: Lei YU <mine260309@gmail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/ubi/watch.hpp b/ubi/watch.hpp
index a04967e57..4d195a3e1 100644
--- a/ubi/watch.hpp
+++ b/ubi/watch.hpp
@@ -18,7 +18,7 @@ struct EventSourceDeleter
 {
     void operator()(sd_event_source* eventSource) const
     {
-        eventSource = sd_event_source_unref(eventSource);
+        sd_event_source_unref(eventSource);
     }
 };
 using EventSourcePtr = std::unique_ptr<sd_event_source, EventSourceDeleter>;
@@ -40,7 +40,7 @@ struct CustomFd
      *
      *  @param[in] fd - File descriptor
      */
-    CustomFd(int fd) : fd(fd)
+    explicit CustomFd(int fd) : fd(fd)
     {
     }