Bug 1283340: python: fix .ycm_extra_conf.py for python 3 r=gps

MozReview-Commit-ID: 2HTAftYwZPJ

--HG--
extra : rebase_source : a60cf02829b810b49793fb2b9936554b5130c8c7

.ycm_extra_conf.py

@@ -4,9 +4,12 @@
 
 import imp
 import os
-from StringIO import StringIO
 import shlex
 import sys
+try:
+    from StringIO import StringIO
+except ImportError:
+    from io import StringIO
 
 old_bytecode = sys.dont_write_bytecode
 sys.dont_write_bytecode = True