Show the correct mutex type (even if its just the enum id) rather than the...

Show the correct mutex type (even if its just the enum id) rather than the default one, if it fails.
Suggested by: Ruediger Pluem


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@723666 13f79535-47bb-0310-9956-ffa450edef68