Remove share from local oc_share if OCM invites errored

[michielbdejong]

The MixedGroupShareProvider first adds an entry into oc_share and then sends OCM invites.
When this fails, the local share should be removed from the oc_share table.

[thepeak99]

Related to #31.

Needs more discussion

[soltanireza65]

@michielbdejong
can you pls just write down the scenario so that I can follow it through the code?
I do not know how MixedGroupShareProvider relates to the issue,
because sharing a file with a remote group is in the files_sharing app which we have replaced the controllers in ocm app

[soltanireza65]

so the flow starts with files_sharing/lib/Share20OcsController:createShare

[soltanireza65]

I just found the flow
it was our (OCM app) AbstractFederatedShareProvider::createFederatedShare that handles this
and if the result happens to be a failure it calls removeShareFromTableById to remove the created share from local oc_share

this is the scenario that I have tested:
stopped the oc2.docker service
and try to share a file with [email protected]
so because remote servers were not available, then the $result happens to be false,