repair: directly use repo.vfs.join
The 'repo.join' method is about to be deprecated.
--- a/mercurial/repair.py Wed Mar 08 16:53:32 2017 -0800
+++ b/mercurial/repair.py Wed Mar 08 16:53:39 2017 -0800
@@ -886,7 +886,7 @@
backupvfs = vfsmod.vfs(backuppath)
# Make a backup of requires file first, as it is the first to be modified.
- util.copyfile(srcrepo.join('requires'), backupvfs.join('requires'))
+ util.copyfile(srcrepo.vfs.join('requires'), backupvfs.join('requires'))
# We install an arbitrary requirement that clients must not support
# as a mechanism to lock out new clients during the data swap. This is