CDRIVER-2621 write concern default bug fixed
CDRIVER-2621 write concern default bug fixed

acmorrow/mongo-c-driver,jmikola/mongo-c-driver,rcsanchez97/mongo-c-driver,beingmeta/mongo-c-driver,mongodb/mongo-c-driver,beingmeta/mongo-c-driver,jmikola/mongo-c-driver,jmikola/mongo-c-driver,acmorrow/mongo-c-driver,mongodb/mongo-c-driver,acmorrow/mongo-c-driver,jmikola/mongo-c-driver,mongodb/mongo-c-driver,mongodb/mongo-c-driver,beingmeta/mongo-c-driver,mongodb/mongo-c-driver,acmorrow/mongo-c-driver,beingmeta/mongo-c-driver,rcsanchez97/mongo-c-driver,derickr/mongo-c-driver,rcsanchez97/mongo-c-driver,derickr/mongo-c-driver,acmorrow/mongo-c-driver,acmorrow/mongo-c-driver,beingmeta/mongo-c-driver,derickr/mongo-c-driver,jmikola/mongo-c-driver,beingmeta/mongo-c-driver,rcsanchez97/mongo-c-driver,beingmeta/mongo-c-driver,derickr/mongo-c-driver,acmorrow/mongo-c-driver,mongodb/mongo-c-driver,beingmeta/mongo-c-driver,jmikola/mongo-c-driver,derickr/mongo-c-driver,rcsanchez97/mongo-c-driver,jmikola/mongo-c-driver,mongodb/mongo-c-driver,rcsanchez97/mongo-c-driver,derickr/mongo-c-driver,rcsanchez97/mongo-c-driver,derickr/mongo-c-driver