[WIFICOND][API] Simplify initialization sequence

Per API council request: rename 'initialize' to the only function
it (really) executed - setting up a death listener.

Bug: 148680192
Test: atest android.net.wifi
Test: atest com.android.server.wifi
Change-Id: I0857f1b550f6bdae039dae76b663bc2813dc5bdb
3 files changed