Ensure we are able to fetch the upstream share

* If a block was found but the upstream share is not inserted, bail out
* Next run should find the upstream share if it was added properly

Should address #189 but maybe not a fix yet.
Properly detect if we did find an upstream share

Avoid returning true even if no share was found.

Addresses #189
Merge pull request #208 from TheSerapher/issue-189

Issue 189