Use BTN_LEFT instead of BTN_MOUSE in VirtualBox

Open-webOS-DCO-1.0-Signed-off-by: Keith Derrick <keith.derrick@palm.com>

Change-Id: Icd327ea1deb75e6401a7108ed435fc89038f363c
Reviewed-on: http://g2g.palm.com/1311
Reviewed-by: Build Verification
Reviewed-by: Keith Derrick <keith.derrick@palm.com>
Tested-by: Keith Derrick <keith.derrick@palm.com>
Reviewed-by: Sapna Todwal <sapna.todwal@palm.com>