remove default add of Expect 100 Continue header
-Dsun.net.http.allowRestrictedHeaders=true required for Expect header to passthrough
do not send payload when method doesn't send payload
dynect: cleaner approach to sending non-standard Content-Type on GET
atmos: explicitly set Expect header on methods that need it
swift: explicitly set Expect header on methods that need it
s3: explicitly set Expect header on methods that need it
azureblob: explicitly set Expect header on methods that need it
Merge pull request #1383 from jclouds/remove-expect-100

remove default add of Expect 100 Continue header