package/sconeserver: unconditionally needs host-pkgconf

sconeserver uses pkg-config macros and uses autoreconf, so it
unconditionally needs host-pkgconf.

[Peter: drop host-pkgconf from sub options, update description]
Reported-by: Matthew Weber <matt@thewebers.ws>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>