Fixed unexpected variable escaping in svn

I was unable to deploy via SVN, because doublequotes around 'username' and 'password' variables were escaped with backslash, plus there was no space after last doublequote, so generated command was incorrect
`executing locally: "svn info https://mysvnserver.com/trunk --username \"myusername\"--password \"mypassword\"--no-auth-cache  -rHEAD"`

After this fix command ran properly.
`executing locally: "svn info https://mysvnserver.com/trunk  --username 'myusername' --password 'mypassword' --no-auth-cache  -rHEAD"
`

I haven't tested it on anything else but my computer. 

Windows 7 x64
ruby 1.9.3p448 (2013-06-27) [i386-cygwin]
Capistrano v2.15.5

I know this fix is little nasty, but since I don't know ruby, I was unable to dig deeper.