Bug 136028

Current mysql-proxy.sh startup script does not allow use of multiple MySQL
backends due to lack of $mysql_proxy_backend_addresses variable processing.
According to documentation[1] of --proxy-backend-addresses option, it is
possible to specify multiple backend servers by supplying multiple options. But
mysql-proxy.sh just assigns the value of $mysql_proxy_backend_addresses
variable to this option.

The patch allows to use multiple MySQL backend servers by specifying multiple
--proxy-backend-addresses options for each host:port pair in
$mysql_proxy_backend_addresses variable to mysql-proxy command arguments line.

Example of usage:

rc.conf:

mysql_proxy_enable="yes"
mysql_proxy_backend_addresses="10.10.155.201:3306 10.10.155.202:3306"

root@127.0.0.1[(none)]$ select * from proxy_config;
+----------------------------+--------------------+
| option                     | value              |
+----------------------------+--------------------+
| admin.address              | 127.0.0.1:3306     |
| proxy.address              | 10.10.155.203:3306 |
| proxy.lua_script           | NULL               |
| proxy.backend_addresses[0] | 10.10.155.201:3306 |  <====
| proxy.backend_addresses[1] | 10.10.155.202:3306 |  <====
| proxy.fix_bug_25371        | 0                  |
| proxy.profiling            | 1                  |
+----------------------------+--------------------+
7 rows in set (0.00 sec)


[1] http://dev.mysql.com/doc/refman/5.0/en/mysql-proxy-cmdline.html

How-To-Repeat: Just try to use more than one MySQL backend addresses.