Suggested fix for "modulemissingcode" error while running course participation report

*getview_actions() and *getpost_actions() were missing from ouwiki/lib.php

Hope I got all the "action"s right :-)

I am basing my action logging suggestions on the attached usage count for various ouwiki "action"s on one of our servers.

ACTION	COUNT( * )
add	29
annotate	2
diff	56
edit	1205
entirewiki	36
history	216
lock	2
participation	169
revert	21
search	6
unlock	1
update	36
userparticipation	134
view	3459
view all	1
viewold	131
wikihistory	173
wikiindex	256