lib/oe/utils: 'Fix' oe.utils.contains() behaviour

lib/oe/utils: 'Fix' oe.utils.contains() behaviour

Currently oe.utils.contains(X, "A", true, false) will return true for substring matches,
e.g. if X = "ABC". This is not what most users expect from the function.

In the common OE use of this function there is the case of "touchscreen" and "screen" being
used as independent variables. Whilst it could be argued there isn't a problem in that
specific case (touchscreens are usually on screens), there is no substring usage of this
function is OE-Core so this patch changes the behaviour to match only full strings.

It also fixes a bug where duplicate entries would confuse multiple matches, e.g.
contains(X, ["A", "B"], ...) would match X = "A A" which is clearly wrong.

(From OE-Core rev: 5c09cbe3bf456e968fc853827698eb18b62e8348)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>