[gnucash] (3 commits) ...Drop gnc-test-env (#644933, CVE-2010-3999)

[Bill Nottingham]

Summary of changes:

  7498732... Update to 2.3.15. Add upstream patch for config migration.  (*)
  8de750a... Update source tarball to 2.3.15 (*)
  c53c057... Drop gnc-test-env (#644933, CVE-2010-3999) (*)

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