Fix error message case in two cfail test

I had made the error consistent with other errors, but forgot to
also change the tests.

Author: marijnh

src/test/compile-fail/nested-ty-params.rs

@@ -1,4 +1,4 @@
-// error-pattern:Attempt to use a type argument out of scope
+// error-pattern:attempt to use a type argument out of scope
 fn hd<U>(v: [U]) -> U {
     fn hd1(w: [U]) -> U { ret w[0]; }
 

src/test/compile-fail/type-arg-out-of-scope.rs

@@ -1,4 +1,4 @@
-// error-pattern:Attempt to use a type argument out of scope
+// error-pattern:attempt to use a type argument out of scope
 fn foo<T>(x: T) {
     fn bar(f: fn(T) -> T) { }
 }