osd/ClassHandler.cc: uninit var in ctor

CID 717336: Uninitialized pointer field (UNINIT_CTOR)At (2): Non-static class
member "handler" is not initialized in this constructor nor in any functions
that it calls.

Signed-off-by: Samuel Just <sam.just@inktank.com>

src/osd/ClassHandler.h

@@ -53,6 +53,7 @@ public:
     ClassMethod *_get_method(const char *mname);
 
     ClassData() : status(CLASS_UNKNOWN), 
+		  handler(NULL),
 		  handle(NULL) {}
     ~ClassData() { }