py3: open temporary file in binary mode

Otherwise things fail later when we write bytes to the handle.

Differential Revision: https://phab.mercurial-scm.org/D2148

mercurial/patch.py

@@ -215,7 +215,7 b' def extract(ui, fileobj):'
 
     data = {}
     fd, tmpname = tempfile.mkstemp(prefix='hg-patch-')
-    tmpfp = os.fdopen(fd, pycompat.sysstr('w'))
+    tmpfp = os.fdopen(fd, pycompat.sysstr('wb'))
     try:
         msg = pycompat.emailparser().parse(fileobj)