[openal-soft/f20] add %{?_isa} to Requires for the -devel subpackage; add a -qt subpackage to host the alsoft-config t

[François Cami]

Summary of changes:

  120c009... add %{?_isa} to Requires for the -devel subpackage; add a - (*)

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