[install-guide] (3 commits) ...BZ#1045205 - Updated information about inst.askmethod in Boot Options and SourceSpoke

[pbokoc]

Summary of changes:

  0dcda8b... BZ#1076963 - updating Recommended partitioning scheme and A (*)
  ff2b5e0... Moving inst.headless into deprecated boot options (*)
  760f614... BZ#1045205 - Updated information about inst.askmethod in Bo (*)

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