patch: upgrade to git patch when removing binary file
Otherwise it may cause data loss when removing binary files in mq with
--git=auto.
% log
<td class="description"><a href="/rev/1b0e7ece6bd6"><a href="http://bts.example.org/issue123">Issue123</a>: fixed the <i class="x">bug</i>!</a><span class="branchhead">default</span> <span class="tag">tip</span> </td>
% errors