Prevent Sym key from showing the IME picker

By default InputMethodManager will popup an IME picker when pressing
the Sym key.

This can be disabled by setting config_symKeyShowsImePicker to false in the
overlay (so the Sym key will show the symbol windows selector for ex.)

Ported from jellybean (was Change-Id: Id61e2d1d66babbb5bd15d7dcf280c1cb76bced46)
http://review.cyanogenmod.org/25787

Signed-off-by: Michael Bestas <mikeioannina@gmail.com>

Change-Id: I5ee2542c081dca14d2e22724cc2616519716dd45