[NEXUS-6790] Rewrite generated yum metadata after merge

commit 98133d3e05919ffc63692f49a47f52fef55b498f
Author: Alin Dreghiciu <adreghiciu@gmail.com>
Date:   Sun Oct 5 12:00:30 2014 +0300

    [NEXUS-6790] Use file system to store changes

commit fc01688fa12dbbff3429c418a5f9a4b24a21ff82
Author: Alin Dreghiciu <adreghiciu@gmail.com>
Date:   Fri Oct 3 20:59:56 2014 +0300

    [NEXUS-6790] Rewrite primary.xml after merge

commit e7068118b4d8860e995c162b031f1fa49b88351a
Author: Alin Dreghiciu <adreghiciu@gmail.com>
Date:   Fri Oct 3 20:59:04 2014 +0300

    [NEXUS-6790] Open up DigersterUtils to any algorithm

commit 8f3dd74f0a55ab06de9b2fa7f673bf75af6541af
Author: Alin Dreghiciu <adreghiciu@gmail.com>
Date:   Thu Oct 2 17:03:10 2014 +0300

    [NEXUS-6702] Do not set yum urls on createrepo