Update WifiConfiguration in AccessPoint.

Currently, calling AccessPoint.update(config, info, networkInfo) will
not store the new WifiConfiguration object if it has changed. This can
cause the summary statement to fall out of sync.

Bug: b/38409294
Test: Open WifiNetworkDetails page with verbose logging. Stale state no
longer shown when config changes.
runtest --path
frameworks/base/packages/SettingsLib/tests/integ/src/com/android/settingslib/wifi/AccessPointTest.java

Change-Id: I86411527472621f86ab691ee772c0b3d2153d01f