Fixes for async response to SO

1) Wrong user name configured for SO interface
2) Accept header needs to be set to 'text/plain'
3) Content-Type needs to be explicitly set to 'application/json'
4) Template is missing outer "input" tag
5) Message needs to be in XML format, not JSON

Change-Id: Icd06d12ff8576d2dd560ea452d0a14c3de643a00
Issue-ID: SDNC-927
Signed-off-by: Timoney, Dan (dt5972) <dtimoney@att.com>