Clear WiFi bitset variables before reading them from supplicant

Otherwise if the config that is being filled in may have some bits
already set.
Also refactored repetitive code.

Bug: 21152481
Change-Id: I3506c4b2472577dd355e94d40783c2c1dd31dc98
1 file changed
tree: ed2af7dc933625cd15d70c0d81d76896c8c9d8df
  1. service/