META-INF: update-binary: Clean up before starting the flashing process

In this way if there were files left from previous installations they get deleted.

META-INF/com/google/android/update-binary

@@ -28,6 +28,7 @@ abort() { ui_print "$*"; umount /system; umount /data; exit 1; }
 
 show_progress 1.34 4;
 ui_print " ";
+cleanup;
 mkdir -p /tmp/anykernel/bin;
 cd /tmp/anykernel;
 unzip -o "$ZIP";