Fix a faulty logic in PMSingleDeviceDiscovery

Fix a faulty logic in PMSingleDeviceDiscovery

A device discovery transaction should be removed AFTER port discovery
is done or discovery time is expired.

Change-Id: I55062a3a8ef5187bf249d0afee2276e40c0f52d9
Signed-off-by: Jihun Ha <jihun.ha@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/13167
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Joonghwan Lee <jh05.lee@samsung.com>
Reviewed-by: Heewon Park <h_w.park@samsung.com>
Reviewed-by: Randeep Singh <randeep.s@samsung.com>