fix cppcheck warning

- Fix warnings:
  [noExplicitConstructor]
  ipmi/manualcmds.hpp:20:5: style: Class 'ZoneControlIpmiHandler' has a
      constructor with 1 argument that is not explicit.

  [redundantInitialization]
  dbus/dbusutil.cpp:96:15: style: Redundant initialization for 'layer'.
      The initialized value is overwritten before it is read.

  [uninitMemberVar]
  pid/pidcontroller.hpp:23:5: warning: Member variable
      'PIDController::_pid_info' is not initialized in the constructor.

  [memsetClassFloat]
  pid/util.cpp:29:10: portability: Using memset() on struct which
      contains a floating point number.

  [constParameter]
  ipmi/manualcmds.cpp:108:72: style: Parameter 'dataLen' can be
      declared as pointer to const

Signed-off-by: Harvey Wu <Harvey.Wu@quantatw.com>
Change-Id: Ib368c6e3a609e446529573cd0b9fa03858232db1
diff --git a/ipmi/manualcmds.hpp b/ipmi/manualcmds.hpp
index 4e11662..057ffc9 100644
--- a/ipmi/manualcmds.hpp
+++ b/ipmi/manualcmds.hpp
@@ -17,7 +17,8 @@
 class ZoneControlIpmiHandler
 {
   public:
-    ZoneControlIpmiHandler(std::unique_ptr<ZoneControlInterface> control) :
+    explicit ZoneControlIpmiHandler(
+        std::unique_ptr<ZoneControlInterface> control) :
         _control(std::move(control))
     {}
 
@@ -28,7 +29,7 @@
                                   size_t* dataLen);
 
     ipmi_ret_t setManualModeState(const uint8_t* reqBuf, uint8_t* replyBuf,
-                                  size_t* dataLen);
+                                  const size_t* dataLen);
 
   private:
     std::unique_ptr<ZoneControlInterface> _control;