git svn info: always quote URLs in 'info' output

git svn info: always quote URLs in 'info' output

Changes 'git svn info' to always URL-escape the 'URL' and 'Repository'
fields and --url output, like SVN (at least 1.5) does.

Note that reusing the escape_url() further down in Git::SVN::Ra is not
possible because it only triggers for http(s) URLs.  I did not know
whether extending it to all schemes would break SVN access anywhere,
so I made a new one that quotes in all schemes.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Acked-by: Eric Wong <normalperson@yhbt.net>