[FIX] search view field visible through dropdown menu

xmo@openerp.com-20130305093619-s1e5fbl80r7qnk5l added zIndex on wrong
element of search view (view itself instead of just the autocompletion
drop-down) leading to the search view text field being visible over
the "more" section of the menu.

Move zIndex setting to the right place (on the missing
`autocomplete('widget')` indirection, and on open as jquery ui
autocomplete apparently decides to reset the dropdown's z-index each
time it is open)

bzr revid: xmo@openerp.com-20130306110051-1wfhxaylsn71skjp