Fix tab show/shown handlers for bootstrap v3

Also remove preventDefault() call from tab 'show' handler -
with that call it required 2 clicks to switch to a
lazy-loaded tab.

Change-Id: I4ba55c6f750cb9724287d5a9f2297666c0cece01
Closes-Bug: #1347002
Closes-Bug: #1350117
Merge "Fix tab show/shown handlers for bootstrap v3"