AppFW test cases: Update README example-session is not valid for exmaple-app ,so remove related info Add more info for M2 verification cases.
AppFW test cases: Update README
example-session is not valid for exmaple-app ,so remove related info
Add more info for M2 verification cases.

Signed-off-by: Wu Dawei <b8fdb5b9f0b6b29b63287bce074c688ca08d8ead@intel.com>

daweiwu/meta-iotqa-1,ostroproject/meta-iotqa,wanghongjuan/meta-iotqa-1,ostroproject/meta-iotqa,daweiwu/meta-iotqa-1,ostroproject/meta-iotqa,daweiwu/meta-iotqa-1,ostroproject/meta-iotqa,wanghongjuan/meta-iotqa-1,daweiwu/meta-iotqa-1,wanghongjuan/meta-iotqa-1,ostroproject/meta-iotqa,wanghongjuan/meta-iotqa-1,wanghongjuan/meta-iotqa-1,daweiwu/meta-iotqa-1