Emit an error code when dol diff does not match (#43)

* Emit an error code when `dol diff` does not match

* `exit(1)` instead of `bail`

src/cmd/dol.rs

@@ -1534,7 +1534,7 @@ fn diff(args: DiffArgs) -> Result<()> {
                     linked_sym.address,
                 );
             }
-            return Ok(());
+            std::process::exit(1);
         }
     }
 
@@ -1575,7 +1575,7 @@ fn diff(args: DiffArgs) -> Result<()> {
             );
             log::error!("Original: {}", hex::encode_upper(orig_data));
             log::error!("Linked:   {}", hex::encode_upper(linked_data));
-            return Ok(());
+            std::process::exit(1);
         }
     }