bitbake: data_smart: Move getVar expand cache handing to fix _remove operations

bitbake: data_smart: Move getVar expand cache handing to fix _remove operations

DISTRO_FEATURES_remove = "opengl" wasn't working as expected. The reason
turned out the be the indirect reference to opengl and the fact _remove was
operating on unexpanded data.

This patch rearranges some code to ensure we operate on expanded data
by moving the expand cache handing into getVarFlags instead of getVar.

(Bitbake rev: 181899bd9665f74f8d1b22d2453616ad30d26d9e)

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