Only move mysql data files if they exist

On first boot (on Fedora at least), these might not exist causing
the mv commands to fail.

Change-Id: I6bff5ab26d863c8991e11f11ee21c400211f70ec
Install link to mysql unix socket

Default mysql socket for Fedora/RHEL mysql client lib is
/var/lib/mysql/mysql.sock.  Although we change this path in a mysql
config file, it's not sufficient because some clients don't read any
mysql config and just use default socket path.

For Fedora/RHEL this patch installs a link at the origional path.

Change-Id: Id46961278c9d33d04d555f14d8334c5fe2cb23c7
Use [client] instead of [mysql] in my.cnf

The [mysql] group technically only informs the command line client. We
should be using the [client] group which will inform libmysqlclient in
general. Note that there are still going to be programs that bypass this
file so it is not a perfect solution to the problem of different
binaries having different compiled in defaults for the socket.

Change-Id: Ic82a976b8591ef3a19e45f36ecc210104e670734
Merge "Install link to mysql unix socket"