bug with task svn:set_current_revision

When running task svn:set_current_revision, I am getting this error in console window:
DEBUG [31ec45ba] Running /usr/bin/env svn log -r HEAD -q | tail -n 2 | head -n 1 | sed s/ |.*/''/ on 
DEBUG [31ec45ba] Command: cd /home/xxx/apps/xxx/repo && /usr/bin/env svn log -r HEAD -q | tail -n 2 | head -n 1 | sed s/ |.*/''/
DEBUG [31ec45ba] 	bash: ./: is a directory

So I changed the svn.rb, fix it.