krb5: Update to new upstream version 1.12.1
libverto: Use libverto 0.2.4 from Ubuntu 14.04 on 12.04. Needed by krb5-1.12.1
libverto: Update to upstream version 0.2.6
krb5: Take out substpdf target as it is currently broken on Ubuntu 12.04
targets.
krb5: Fix dependencies
Merge pull request #4 from opinsys/krb5-1.12.1

Update MIT krb5 to v1.12.1, includes libverto update to 0.2.6.