check for existence of path on replicate adapter
applyPathPrefix is applied by getObject
Merge pull request #264 from basz/fix/double-prefix-on-rackspace-has

applyPathPrefix is applied by getObject
Fixed Rackspace double path prefixing.
Updated changelog with recent changed.
Merge pull request #261 from basz/fix/replicate-adapter-update

check for existence of path on replicate adapter