buildbot exception in on httpd-trunk

[buildbot]

The Buildbot has detected a build exception on builder httpd-trunk while 
building . Full details are available at:
    https://ci.apache.org/builders/httpd-trunk/builds/2841

Buildbot URL: https://ci.apache.org/

Buildslave for this Build: bb_slave6_ubuntu

Build Reason: The Nightly scheduler named 'httpd-trunk-nightly-clean' triggered 
this build
Build Source Stamp: [branch httpd/httpd/trunk] HEAD
Blamelist: 

BUILD FAILED: exception svn (clean)

Sincerely,
 -The Buildbot