WifiConfiguration can have been build by an app with a NULL SSID, or other null fields. We need to verify that at least that those fields are not NULL before using them. More specifically, don't crash when enabling an AP with a null SSID in setApConfiguration function. Bug: 14568953 Change-Id: I6b33ddf97789c0ee4b850d3ec0bccb08100c21d5