ENYO-261 Remove silence method to cover direct calling of setSelectedIndex()

Enyo-DCO-1.1-Signed-off-by: David Um david.um@lge.com
remove call to silence() and unsilence()
Merge pull request #1634 from enyojs/ENYO-261-davidum

ENYO-261 Remove silence() to cover direct calling of setSelectedIndex()