svn commit hangs over https+kerberos

[GoogleCodeExporter]

What steps will reproduce the problem?
1. from my account I do su root (with domain passwd)
2. svn commit -m "test"
3. now svn hangs forever

In apache log I see lots of:
[Fri May 30 15:54:08 2014] [error] [client 172.20.4.10] access to 
/portage-overlay/!svn/me failed, reason: user 'root' does not meet 
'require'ments for user/valid-user to be allowed access

I expect svn/serf to use my normal user credentials(as svn 1.7.x does) instead
of insisting on root's creds.

On gentoo linux with subversion 1.8.9 and serf 1.3.5(tried serf in svn trunk 
too) 

Original issue reported on code.google.com by [email protected] on 30 May 2014 at 3:18