IPv6 on, forgetest dual-stack, the release rootfs sheds 22 MB

The distro keeps its ipv6 feature (busybox networking and ifupdown
inet6, openssh, ntp and rsyslog follow); forgetest binds "::" by
default, one dual-stack socket that still serves IPv4. The release
image drops nano (with it file and the libmagic database, 8.7 MB; the
dev image keeps nano), the udev hardware database (7.7 MB of USB and
PCI identities for buses the board lacks, via BAD_RECOMMENDATIONS) and
urllib3's pyOpenSSL/cryptography recommendation (6 MB; nothing imports
them, TLS goes through the standard library). BRINGUP item 21 records
the round and the bench checks it owes; item 16 gets its re-measure
plan on the UP kernel with the performance governor.

Coverage: image.* covers the rootfs composition and the distro conf
(platform); forgetest's own suite covers the server.

meta-forgefirm/conf/distro/forgefirm.conf

@@ -5,7 +5,7 @@ DISTRO_NAME = "OpenGlow/ForgeFIRM"
 DISTRO_VERSION = "0.0.0"
 
 DISTRO_FEATURES:remove = " \
-  3g alsa avahi bluetooth bluez5 ext2 ipv6 irda nfc nfs pci pcmcia \
+  3g alsa avahi bluetooth bluez5 ext2 irda nfc nfs pci pcmcia \
   pulseaudio vulkan wayland x11 zeroconf "
 
 # opengl stays: forgectrl's camera demosaic runs as GLES2 fragment
@@ -15,6 +15,9 @@ DISTRO_FEATURES:remove = " \
 # (both remain removed above), so the cost is the libraries and the one
 # driver, not a graphics stack.
 PACKAGECONFIG:pn-mesa = "opengl gles egl gbm gallium etnaviv"
+# udev's hardware database is USB and PCI vendor/product identities (7.7 MB);
+# the board has neither bus.
+BAD_RECOMMENDATIONS += "eudev-hwdb"
 
 # System logger: rsyslog replaces busybox syslogd/klogd. Every ForgeFIRM
 # process logs through it and it is the only log writer (one directory