This type of check is added for making sure that we can support
custom regions.
ListBuckets and GetBucketLocation are always "us-east-1" rest
should look for the configured region.
Fixes#1278
Signature calculation has now moved out from being a package to
top-level as a layered mechanism.
In case of payload calculation with body, go-routines are initiated
to simultaneously write and calculate shasum. Errors are sent
over the writer so that the lower layer removes the temporary files
properly.
Harshavardhana