MainActivity: fix warnings

app/src/main/java/io/lowrespalmtree/harvestdawn/MainActivity.kt

@@ -46,7 +46,7 @@ class MainActivity : AppCompatActivity() {
 
         ensureWritePermission()
 
-        findViewById<FloatingActionButton>(R.id.fab).setOnClickListener { view ->
+        findViewById<FloatingActionButton>(R.id.fab).setOnClickListener { _ ->
             if (hasWritePermission) {
                 openCamera()
             } else {
@@ -211,7 +211,7 @@ class MainActivity : AppCompatActivity() {
             return when (val rc = FFmpeg.execute(command)) {
                 RETURN_CODE_SUCCESS -> true.also { Log.i(TAG, "Mix succeeded.") }
                 RETURN_CODE_CANCEL -> false.also { Log.i(TAG, "Mix cancelled.") }
-                else -> false .also { Log.e(TAG, "Mix failed!") }
+                else -> false .also { Log.e(TAG, "Mix failed! rc = $rc") }
             }
         }