Think-o in foreign key comments

Hello,

I noticed a few places in the new foreign key code where a comment says 
"the ON DELETE SET NULL/DELETE clause". I believe it should say "ON 
DELETE SET NULL/DEFAULT".

These comments were added in d6f96ed94e7, "Allow specifying column list 
for foreign key ON DELETE SET actions." Here is a patch to correct them. 
I don't think you usually create a commitfest entry for tiny fixes like 
this, right? But if you'd like one please let me know and I'll add it.

Yours,

-- 
Paul              ~{:-)
pj@illuminatedcomputing.com