Completeness regression on simple nonlinear formula

Commit: dc6a8fd
OS: Ubuntu 18.04

```
$ z3-4.8.10 unknown.smt2
unsat
$ z3 unknown.smt2
unknown
$ cat unknown.smt2
(declare-const x Int)
(assert (forall ((v Int)) (or (= 0 (mod v 2)) (> x (+ 6869 v)))))
(check-sat)
```