Fix the crazy RSSI icons.

Codepaths for wifi and mobile were contaminating one
another's data, which is fine when you're only showing one
at a time, but not so good in the general case.

Bug: 3481508
Bug: 5159559
Bug: 5161130
Bug: 5163206
Change-Id: I64e6f5ebd07a5b0777e7296b1c210195431e4ce6