Bug 1100 - Invoking an RPC with no input should not throw 500 when expected

Patch Set 3:
*Modified the Json/Xml readers to not throw an except if the content is empty
*Moved the validation of non empty object into restconf where the knowledge
of what is expected exists.

Change-Id: I4e689770d1a6843e99ce498bd12cecc5e1817eaa
Signed-off-by: Devin Avery <devin.avery@brocade.com>
Merge "Bug 1100 - Invoking an RPC with no input should not throw 500 when expected"