Moved a MySQL Database to another server, but socket keeps pointing to localhost
It is a socket file used for inter-process communication, you have to stop the local MySQL server and make sure the mysql.sock doesn't exist. Then you have to re-create the socket file to send the connection to the correct destination (in your case, it is Amazon RDS).

There are many ways to create a socket file, for example you can use socat, and the command is (you may have to modify to your settings) -

socat UNIX-LISTEN:/path/to/mysql.sock,fork,reuseaddr,unlink-early,user=mysql,group=mysql,mode=777 TCP:&lt;Amazon RDS Server&gt;:3306 &amp;

Source: http://linux.die.net/man/1/socat

Note: This isn't the right way to fix this, so you may want to check the bnconfig script to get a proper fix.