Improve yum cache handling
Improve yum cache handling

This fixes following problem:
Not using downloaded repomd.xml because it is older than what we have:
  Current   : Mon Jan 13 03:34:38 2014
  Downloaded: Mon Jan 13 03:34:36 2014

misli/softwarecollections,misli/softwarecollections,misli/softwarecollections,misli/softwarecollections