SQL-Sync doesn't work with aliases

Function drush_sql_sync get as arguments just aliases: @local and etc. In the new version https://github.com/drush-ops/drush/commit/23c461f225a3aa674f2ac2844e853addf362011f was added code which set $runner based on alias. But $source and $destination it's always just string and all commands always runs on the destination.

As result commands always runs on the source server.

I added code which gets alias settings for source and destination instead of comparing with alias name.