Ensure that Apache is running with MPM=Prefork

Script wsgi.py checks if Apache is compiled with MPM=Prefork
and if not, it refuses to run.

https://fedorahosted.org/freeipa/ticket/252

install/share/wsgi.py

@@ -22,4 +22,8 @@ else:
     api.log.info('*** PROCESS START ***')
 
     # This is the WSGI callable:
-    application = api.Backend.session
+    def application(environ, start_response):
+        if not environ['wsgi.multithread']:
+            return api.Backend.session(environ, start_response)
+        else:
+            api.log.error("IPA does not work with the threaded MPM, use the pre-fork MPM")