Correct SVN bug

This pull request contains two commits :
* The first one rename a misnamed local variable in \_lp_svn_branch_color (not really important fix).
* The second one remove useless quotes in the \_lp_escape of \_lp_svn_branch. Normally, it fixes the bug identified on SVN prompts. I tested it on http://www.andre-simon.de/doku/highlight/en/sfnet.php.