Issue with try_sudo deploy

Hi,
First of all thank you for your gem.
I've found bug with using sudo for deploy. If you use sudo and other user for deploy (as ex. deployuser) you will see next error:
```
-> "else" :: "sudo -p 'sudo password: ' -u deployuser if [ -d /home/deployuser/deploy1/releases/20130614115355/assets ] ; then rm -rf /home/deployuser/deploy1/releases/20130614115355/assets; fi"
    servers: ["PS1", "PS2"]
    [PS1] executing command
 ** [out :: PS1] sh: -c: line 0: syntax error near unexpected token `then'
 ** [out :: PS1] sh: -c: line 0: `sudo -p 'sudo password: ' -u deployuser if [ -d /home/deployuser/deploy1/releases/20130614115355/assets ] ; then rm -rf /home/deployuser/deploy1/releases/20130614115355/assets; fi'
    [PS2] executing command
 ** [out :: PS2] sh: -c: line 0: syntax error near unexpected token `then'
 ** [out :: PS2] sh: -c: line 0: `sudo -p 'sudo password: ' -u deployuser if [ -d /home/deployuser/deploy1/releases/20130614115355/assets ] ; then rm -rf /home/deployuser/deploy1/releases/20130614115355/assets; fi'
    command finished in 72ms
*** [deploy:update_code] rolling back
```
I've fixed this issue.