patchbomb: continue if we can't import readline.

contrib/patchbomb

@@ -52,13 +52,18 b' from mercurial import hg'
 from mercurial import ui
 import os
 import popen2
-import readline
 import smtplib
 import socket
 import sys
 import tempfile
 import time
 
+try:
+    # readline gives raw_input editing capabilities, but is not
+    # present on windows
+    import readline
+except ImportError: pass
+
 def diffstat(patch):
     fd, name = tempfile.mkstemp()
     try: