Bug fix for building the hover target list

lastHoverTarget should be updated even though lastHoverTarget is not null.
If not, the hover target list cannot have more than one hover target.

Change-Id: I21b49e8cbf3657321b2f1f2c20a3bdeb7f07bd48
Signed-off-by: Sangkyu Lee <sk82.lee@lge.com>