logic to remove prop from id for prop changed events

[yulgit1]

curl -X PATCH -H "Content-Type: application/sparql-update" "http://localhost:8080/rest/test1/indexableObj2" -d "@sparqlupdate.txt"
PREFIX rdf: http://www.w3.org./1999/02/22-rdf-syntax-ns#
PREFIX dc: http://purl.org/dc/elements/1.1/
INSERT {
<> rdf:type http://purl.org/dc/elements/1.1/describable ;
dc:title "update3-some-resource-title" ;
dc:creator "some3-resource-creator"
}
WHERE { }

Results in 1 prop changed events with id "/test1/indexableObj2/dc:title". Check for this condition and remove property.

[ajs6f]

Looks like a merge problem...?
Also, could you add a test to demonstrate the condition we're guaranteeing with this change? Perhaps just a unit test would be fine, or you could add something to IndexerGroupIT?