GpsLocationProvider: Fix race condition while bringing up APN for SUPL.

If handleUpdateNetworkState() is called before
ConnectivityManager.startUsingNetworkFeature() returns, then we will not
call native_agps_data_conn_open() to inform the GPS that the APN is up.
So we now set mAGpsDataConnectionState to AGPS_DATA_CONNECTION_OPENING
before calling ConnectivityManager.startUsingNetworkFeature() to avoid
this problem.

Change-Id: I5e1597d6494dc8ab68e608911c546a7a04f2ea07
Signed-off-by: Mike Lockwood <lockwood@android.com>