libtracker-data: Do not error out when deleting non-existing statement
libtracker-data: Do not error out when deleting non-existing statement

There is no need to report an error for domain mismatch on delete.
This fixes DELETE { <foo:bar> ?p ?v } WHERE { <foo:bar> ?p ?v}

outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker