Bug 1094177: Call |Keystore::Shutdown| to cleanup key store, r=chucklee
Bug 1094177: Fix VIM modelines in implementation of key store, r=chucklee

This patch modifies the VIM modelines in |KeyStore.{cpp,h}| to match
Mozilla's coding style.
Bug 1094177: Convert |KeyStore| to use |{Listen|Stream}Socket|, r=chucklee

With the use of separate listen and stream sockets in |KeyStore|, the
listen socket remains open while |KeyStore| serves a connected client
on the stream socket. When the client disconnected, |KeyStore| continues
to listen for the next connection request.

The old dependency on |UnixSocketConsumer| has been removed.