[PATCH] patch: remove unused fsbackend._join()

[Martin von Zweigbergk]

# HG changeset patch
# User Martin von Zweigbergk <martinvonz at google.com>
# Date 1498802687 25200
#      Thu Jun 29 23:04:47 2017 -0700
# Node ID dd379552c909738a96fae181e8a6f132034f2b60
# Parent  40ee74bfa11122a0a3ab74186f5056243b84af89
patch: remove unused fsbackend._join()

The function lost its last caller in 2a095d3442e0 (patch: replace
functions in fsbackend to use vfs, 2014-06-05) when the callers
started relying on the opener to do the join.

diff --git a/mercurial/patch.py b/mercurial/patch.py
--- a/mercurial/patch.py
+++ b/mercurial/patch.py
@@ -453,9 +453,6 @@
         super(fsbackend, self).__init__(ui)
         self.opener = vfsmod.vfs(basedir)
 
-    def _join(self, f):
-        return os.path.join(self.opener.base, f)
-
     def getfile(self, fname):
         if self.opener.islink(fname):
             return (self.opener.readlink(fname), (True, False))