Fix bug for discover logic on consumer service.

Fix bug for discover logic on consumer service.

1) Modify default connectivity type of discover requestion.
When consumer service run the discover provider,
Connectivity type of request was CT_DEFAULT.
It original meaning was CT_ADAPTER_IP.

2) Remove meaningless memory allocation.
When discover as TCP, we use of allocated context data.
But, this context data unnecessary to allocate.

Change-Id: I2fab71f5352485f04b17b3e7fdd9cda254ebeab9
Signed-off-by: KIM JungYong <jyong2.kim@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/11017
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>