remove require jquery.ui.autocomplete

From jquery-ui-rials ver. 5 ( https://github.com/joliss/jquery-ui-rails ) the syntax for require changed.
In previous versions it was:
 *= require jquery.ui.autocomplete
now it is:
 *= require jquery-ui/autocomplete
I suggest to remove the require from scoped search gem, so that the users of the gem will be able
to require the version that they prefer.