LB-509: Chained Blogs - On provider delete the chained blogs are not deleted

Fetch Source Id so that source can be unchained without reloading.
Merge pull request #113 from petrjasek/liveblog-14

LB-509: Chained Blogs - On provider delete the chained blogs are not del...
Merge remote-tracking branch 'sourcefabric/master' into devel