This is a simple rename that only affects clients.

Next diffs will be:

• native migration to replace connection.showDisconnectedBar with connection.reachable WHERE reachable will be initially set to !showDisconnectedBar
• Same as above, but for web.
• Modify keyserver to serve showDisconnectedBar for old clients and reachable for new clients.

This is a straightforward rename. The next diffs in the stack will need to be tested thoroughly.