Empty index xml input stream

[olenagerasimova]

RpmMetadata.Remove and RpmMetadata.Append should properly handle the case, when empty index xml in provided as input stream. By empty index xml I mean valid xml for empty repository:

<?xml version="1.0" encoding="UTF-8"?>
<metadata xmlns="http://linux.duke.edu/metadata/other" packages="0"/>

[olenagerasimova]

@rultor release, tag=1.7

[rultor]

@rultor release, tag=1.7

@olenagerasimova OK, I will release it now. Please check the progress here

[rultor]

@rultor release, tag=1.7

@olenagerasimova Done! FYI, the full log is here (took me 10min)