Fixed ESP8266 nullpointer dereference.
Fixed ESP8266 nullpointer dereference.

andcor02/mbed-os,andcor02/mbed-os,mbedmicro/mbed,mbedmicro/mbed,kjbracey-arm/mbed,kjbracey-arm/mbed,mbedmicro/mbed,andcor02/mbed-os,andcor02/mbed-os,andcor02/mbed-os,andcor02/mbed-os,mbedmicro/mbed,kjbracey-arm/mbed,mbedmicro/mbed,kjbracey-arm/mbed