delete unnecessary memmove
delete unnecessary memmove

During CDRIVER-2266 this memmove call, which had once served a purpose,
became a logical no-op.

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