LB-843: When chained blog source is shown one of chained blogs should be selected

Fixed.
Merge pull request #256 from petrjasek/lb-842-source-origin-uri

Lb 842 source origin uri
Merge pull request #255 from eozan/LB-843

LB-843: When chained blog source is shown one of chained blogs should be selected
LB-842: When a chained blog provider is deleted, the already selected blogs still appear on chained blog source

Fix OriginURI to be external url of the provider.