explorer: Incorrect usage of realloc

base\shell\explorer\shell\fatfs.cpp 473 error Common realloc mistake: '_CacheSec' nulled but not freed upon failure
base\shell\explorer\shell\fatfs.cpp 474 error Common realloc mistake: '_CacheCnt' nulled but not freed upon failure
base\shell\explorer\shell\fatfs.cpp 475 error Common realloc mistake: '_CacheDty' nulled but not freed upon failure
base\shell\explorer\utility\xs-native.cpp 104 error Common realloc mistake: '_buffer' nulled but not freed upon failure

For more information refer to http://www.cplusplus.com/reference/cstdlib/realloc/