Catch NullPointer caused by race of setting mWifiCond

Similar to ag/25108489, but protecting all places where mWifiCond is
used. Due to many places changed, uses catch exception instead of
synchronized to minimize risk of breaking.

Bug: 327918402
Test: build and flash
Change-Id: I1760a524ac0eedbf21cea84f893be6ffd618d9d9
1 file changed