Auto merge of rust-lang#3002 - RalfJung:miri-script, r=RalfJung

fix oversight from new miri-script

Author: bors

src/tools/miri/tests/compiletest.rs

@@ -76,7 +76,7 @@ fn test_config(target: &str, path: &str, mode: Mode, with_dependencies: bool) ->
     let skip_ui_checks = env::var_os("MIRI_SKIP_UI_CHECKS").is_some();
 
     let output_conflict_handling = match (bless, skip_ui_checks) {
-        (false, false) => OutputConflictHandling::Error("./miri bless".into()),
+        (false, false) => OutputConflictHandling::Error("./miri test --bless".into()),
         (true, false) => OutputConflictHandling::Bless,
         (false, true) => OutputConflictHandling::Ignore,
         (true, true) => panic!("cannot use RUSTC_BLESS and MIRI_SKIP_UI_CHECKS at the same time"),