Using boto instead of boto3

[sgreene570]

When I originally wrote the s3 bindings for this project, the ceph rados gateway for s3 did not support all the features of boto3. Now this is no longer the case, so all the boto code should be replaced with newer boto3 code. Maybe one day I'll be bored enough to fix this myself.

[sgreene570]

@mfrancis95 are you still interested in fixing this issue?

[mfrancis95]

@sgreene570 bet.