IMS-VT: Fix abandoned GLConsumer

Fix abandoned GLConsumer by correcting sequence mismatch of
surface destroy called when the dialog is dismissed and
surfacetexture release

Change-Id: I9583f28c8a675c4c5859b94965341c22f400d013
CRs-Fixed: 630861
Ims: Handle START_READY_EVT and STOP_READY_EVT

1. These two events will be used by Telephony and the VT library to
synchronize camera recording: Start Recording and Stop Recording.
2. Telephony shall start camera recording only after receiving
START_READY_EVT.
3. After receiving STOP_READY_EVT telephony shall wait for
START_READY_EVENT before starting camera recording.

Change-Id: Iee919158ddc8ade5df7deb7225d897f4b629cb27
CRs-Fixed: 621548