[sagemath] (4 commits) ...Correct remaining issues updating to sagemath 6.x build environment

[pcpa]

Summary of changes:

  87008ac... Correct problem when creating a new user (*)
  f2c3d9d... Add missing python-twisted-email requires (#1063061) (*)
  0193196... Rediff sagemath-sagenb.patch due to missing chunk (*)
  89c6752... Correct remaining issues updating to sagemath 6.x build env (*)

(*) This commit already existed in another branch; no separate mail sent