[oe] rrdtool: fixup in EXTRA_OECONF to get past error in do_configure. add do_stage. Closes 2524.

[Rolf Leggewie]

Koen Kooi wrote:
> rd_cv_ieee_works=${rd_cv_ieee_works=yes}

Thanks for noticing and providing an explanation

Fixed in 9767e2c8632f709640f3b42264030553c9906cb2