test: Rebind Log Output Query for PostgreSQL

While debugging a totally unrelated issue, I stumbled over the following
PostgreSQL output:

> [97] ERROR:  syntax error at or near "ORDER" at character 173
> [97] STATEMENT:  SELECT h.event_time, h.event_type FROM history h
>                  JOIN host ON host.id = h.host_id
>                  LEFT JOIN downtime_history d ON d.downtime_id = h.downtime_history_id
>                  WHERE host.name = ?
>                  ORDER BY h.event_time

The relevant code misses a db.Rebind as the "?" character is for MySQL.

tests/history_test.go

@@ -435,12 +435,12 @@ func testHistory(t *testing.T, numNodes int) {
 
 			assert.Equal(t, expected, got, "downtime history should match expected result")
 		}, 5*time.Second, 200*time.Millisecond) {
-			t.Logf("\n%s", utils.MustT(t).String(utils.PrettySelect(db,
+			t.Logf("\n%s", utils.MustT(t).String(utils.PrettySelect(db, db.Rebind(
 				"SELECT h.event_time, h.event_type FROM history h"+
 					" JOIN host ON host.id = h.host_id"+
 					" LEFT JOIN downtime_history d ON d.downtime_id = h.downtime_history_id"+
 					" WHERE host.name = ?"+
-					" ORDER BY h.event_time", hostname)))
+					" ORDER BY h.event_time"), hostname)))
 		}
 
 		testConsistency(t, stream)