Dereference of an explicit null value

Defect 98983 (STATIC_C)
Checker FORWARD_NULL (subcategory deref_constant_null)
File: /src/third_party/wiredtiger/src/session/session_api.c
Function __wt_session_range_truncate
/src/third_party/wiredtiger/src/session/session_api.c, line: 976
Dereferencing null pointer "start".

    		ret = start->next(start);

File: /src/third_party/wiredtiger/src/session/session_api.c
Function __wt_session_range_truncate
/src/third_party/wiredtiger/src/session/session_api.c, line: 1045
Dereferencing null pointer "start".

    		WT_ERR(start->next(start));