Yocto 2.3

Move OpenBMC to Yocto 2.3(pyro).

Tested: Built and verified Witherspoon and Palmetto images
Change-Id: I50744030e771f4850afc2a93a10d3507e76d36bc
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
Resolves: openbmc/openbmc#2461
diff --git a/import-layers/meta-virtualization/conf/layer.conf b/import-layers/meta-virtualization/conf/layer.conf
index f5c1b1e..be08a98 100644
--- a/import-layers/meta-virtualization/conf/layer.conf
+++ b/import-layers/meta-virtualization/conf/layer.conf
@@ -19,3 +19,6 @@
 
 # Override security flags
 require conf/distro/include/virt_security_flags.inc
+
+PREFERRED_PROVIDER_virtual/runc ?= "runc-docker"
+PREFERRED_PROVIDER_virtual/containerd ?= "containerd-docker"