Remove udev-hwdb differently for sumo

Yocto 2.5 will bring us a systemd built with meson, so we will no longer
be able to use EXTRA_OECONF to prevent inclusion of the udev database
in images.

Disable it via BAD_RECOMMENDATIONS in the distro configuration instead.

Tested: Built a witherspoon image
Change-Id: I5eb9239a0f41f65df1823bc4ab6f593a31d2f4ec
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/meta-phosphor/conf/distro/include/phosphor-base.inc b/meta-phosphor/conf/distro/include/phosphor-base.inc
index 203ed74..483e92f 100644
--- a/meta-phosphor/conf/distro/include/phosphor-base.inc
+++ b/meta-phosphor/conf/distro/include/phosphor-base.inc
@@ -70,3 +70,8 @@
 # enabled on a BMC distribution.  Silence the emitted
 # warning.
 SKIP_META_VIRT_SANITY_CHECK = "1"
+
+# Skip the udev database by default.  It adds around 2MB
+# compressed to the root filesystem, and probably doesn't
+# make sense on a BMC anyway.
+BAD_RECOMMENDATIONS_pn-obmc-phosphor-image = "udev-hwdb"