contributions tab does not show contributiosn with NULL contribution_type_id

I'm not sure how it's happened, but somehow we've ended up with some contribution data will NULL contribution_type_id values. (This data could be the result of another bug, but I've tested the contribution data entry forms and I cant find any cases where it accepts blank contribution types)

in any case... if a contribution has NULL for contribution_type_id it will not show up in the contact's contribution tab which seems bad-- I'd like it to show up up there. (Worth mentioning: the number of contributions displayed on the title for the tab does actually count these contribs, which is what I'd expect).

I imagine the fix will involve changing a JOIN to a LEFT JOIN or something similar.