Revert "cap-clause-use-after-move: modernize error msg"

This reverts commit bbda995bfe.

src/test/compile-fail/cap-clause-use-after-move.rs

@@ -1,5 +1,7 @@
+// error-pattern:Unsatisfied precondition constraint
+
 fn main() {
     let x = 5;
     let _y = fn~(move x) { };
-    let _z = x; //~ ERROR use of moved variable: `x`
+    let _z = x; //< error: Unsatisfied precondition constraint
 }