Fix bug 1169995 - Make PATCH with null PK fields force an insert, rather than throwing a NPE
merge tjoneslo: Fix bug 1169995 - Add a check to the select during PATCH such that if a PK field is null note you will never find any matching row, so force the insert processing.

https://code.launchpad.net/~tjoneslo/akiban-server/fix-bug-1169995/+merge/159517