[packman] Building against :Update

[Cristian Morales Vega]

Essentials prj metadata includes things like

  <repository name="openSUSE_11.3">
    <path repository="standard" project="openSUSE.org:openSUSE:11.3:Update"/>
    <arch>x86_64</arch>
    <arch>i586</arch>
  </repository>

It's this on purpose? Usually people builds against openSUSE:11.3
instead of openSUSE:11.3:Update since updates are supposed to be
binary compatible. Notice 11.3 released a glibc security update...
that would mean a rebuild of everything without any change.
Still, it's true that there exists some cases where the original
version was so broken that anything build against it would be also
broken and the :Update version was needed.