Removing most remaining uses of self.connection in Bucket#843

Merged

dhermes merged 3 commits intogoogleapis:masterfrom

dhermes:remove-connection-bucket

May 1, 2015

Commits on Apr 28, 2015

Making Bucket.(exists|create) have an optional connection.
dhermes
committed
Putting optional connection on Bucket.get_blob and DELETE methods.
dhermes
committed
Putting optional connection on Bucket upload methods and copy_blob.
dhermes
committed