Change set position of mAttached

When re-attach network after detaching, mAttached.get() is always false.
Although network is attached in modem side and state is connected,
phone cannot know whether connection state or not.
Because nobody notifies to phone.
So before notifyDataConnection(Phone.REASON_DATA_ATTACHED), set mAttached true

Bug: 10070685
Change-Id: Id1356e1c7e188bd484d892dc4255c3aefc81a032