package.bbclass: Ensure we tell rpmdeps where to find its magic file
Without this, if rpmddeps came from a sstate package which was relocated
it might not find its magic file and if that happens, requires/provides
in packages could get corrupted. This leads to failures at rootfs time
during builds with messages like:
libdbus-1.so.3 is needed by libdbus-glib-1-2-0.92-r1.armv5te
since the provides would be missing in the dbus package.
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
