Prevent nil error when retrieving svn version (#3268).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@2722 e93f8b46-1217-0410-a6f0-8f06a7374b81

lib/redmine/scm/adapters/subversion_adapter.rb

@@ -37,7 +37,7 @@ module Redmine
             version = nil
             shellout(cmd) do |io|
               # Read svn version in first returned line
-              if m = io.gets.match(%r{((\d+\.)+\d+)})
+              if m = io.gets.to_s.match(%r{((\d+\.)+\d+)})
                 version = m[0].scan(%r{\d+}).collect(&:to_i)
               end
             end