tests: Fix ovsdb tests.

tests: Fix ovsdb tests.

This code was updated to use the new name of the schema, but I accidentally
left in the old code to check for the old schema's name.  This worked fine
in my own tests, because I still have a copy of that file sitting around,
but fails on "make distcheck" or a clean source dir.

So this commit deletes the code that checks for the old schema file.