"make clean" should not delete the config.mk
"make clean" should not delete the config.mk

It's very annoying to have to re-run configure after a "make clean".

Signed-off-by: David Scott <63c9eb0ea83039690fefa11afe17873ba8278a56@eu.citrix.com>

thomassa/xenopsd,thomassa/xenopsd,cheng--zhang/xenopsd,euanh/xenopsd,johnelse/xenopsd,djs55/xenopsd,koushikcgit/xenopsd,koushikcgit/xenopsd,djs55/xenopsd,djs55/xenopsd,cheng--zhang/xenopsd,thomassa/xenopsd,johnelse/xenopsd,koushikcgit/xenopsd,euanh/xenopsd,cheng--zhang/xenopsd,johnelse/xenopsd,euanh/xenopsd