Change names of functions not returning Json.
  modified:   storage/connect/json.cpp
  modified:   storage/connect/json.h
  modified:   storage/connect/jsonudf.cpp
  modified:   storage/connect/jsonudf.h
  modified:   storage/connect/mysql-test/connect/r/json_udf.result
  modified:   storage/connect/plugutil.c
  modified:   storage/connect/value.cpp
  modified:   storage/connect/value.h