Do not upload public keys until ping is completed

We cannot upload public keys to the server until the device record
exists.  Kick off ECDHKeyService after the ping response comes in.  This
change has the side effect of always uploading public keys after a ping
happens (daily), which is actually a good thing.

Change-Id: I4f072e0b005298e8db683c1b7d9ffab8e7abda40