[backupserver] Force to use rdiff-backup version 1.0.5+SlapOSPatched001

The recent changes in rdiff backup are not backward compatible.

software/backupserver/software.cfg

@@ -116,14 +116,8 @@ md5sum = 42021b325159dff29e4bd4e33b8ff2f3
 output = ${buildout:directory}/template.cfg
 mode = 0644
 
-[rdiff-backup]
-eggs =
-  ${rdiff-backup-build-1.3.4:egg}
-
 [versions]
-# 1.3.4nxdX is invalid version string, thus pached version string is not '1.3.4nxdX+SlapOSPatched001'
-# but '1.3.4nxdX-SlapOSPatched001'.
-rdiff-backup = 1.3.4nxd6-SlapOSPatched001
+rdiff-backup = 1.0.5+SlapOSPatched001
 gunicorn = 19.1.1
 plone.recipe.command = 1.1
 slapos.recipe.template = 2.4.2